Pathologic Basis of Veterinary Disease

Front Matter
IFC
PATHOLOGIC BASIS of VETERINARY DISEASE
PATHOLOGIC BASIS of VETERINARY DISEASE
Copyright
Contributors
Preface
CONTENTS
Fundamentals for Understanding Veterinary Pathology
Diagnoses in Veterinary Pathology
Language of Veterinary Pathology
Recognition and Interpretation of Lesions
Colors of Normal Tissues and Organs
Evaluation of Lesions Affecting Tissues and Organs
Diagnostic Pathology
I - Cellular and Molecular Mechanisms of Disease (General Pathology)
1 - Mechanisms and Morphology of Cellular Injury, Adaptation, and Deatha
Causes of Cell Injury
Oxygen Deficiency
Physical Agents
Infectious Agents
Nutritional Imbalances
Genetic Derangement
Workload Imbalance
Chemicals, Drugs, and Toxins
Immunologic Dysfunction
Aging
Reversible Cell Injury
Acute Cell Swelling
Mechanisms of Acute Cell Swelling
Acute Cell Swelling Resulting from Hypoxic Injury
Acute Cell Swelling Resulting from Specific Types of Cell Membrane Injury
Carbon Tetrachloride and Cell Membrane Injury
Molecules of the Immune System and Cell Membrane Injury. Cell membranes can also be injured directly by the membrane attack comp...
Morphology of Acute Cell Swelling
Gross Appearance. Acute cell swelling increases the volume and weight of parenchymal organs and imparts pallor to them. It is im...
Microscopic Appearance. The influx of water in hydropic degeneration dilutes the cytosol, separates its organelles, and distends...
Ultrastructural Appearance. Ultrastructurally, the acutely swollen epithelial cell loses plasma membrane structures, such as cil...
Significance and Fate of Acute Cell Swelling
Irreversible Cell Injury and Cell Death
Cell Death
Cell Death by Apoptosis
Extrinsic Apoptosis. Extrinsic apoptosis (see Fig. 1.14) is triggered by alterations in the extracellular milieu and begins with...
Intrinsic Apoptosis. The intrinsic or mitochondrial pathway of apoptosis (see Fig. 1.14) does not entail ligation of a cell surf...
Morphologic Appearance of Apoptosis. Morphologically, apoptosis is a process of chromatin condensation (pyknosis) and nuclear fr...
Cell Death by Oncosis (Oncotic Necrosis)
Regulated Cell Death (RCD) with Morphologic Features of Necrosis. With the discovery that inhibition of caspases did not rescue ...
Cell Membrane Injury Leading to Cell Death. The failure to restore mitochondrial function and repair cell membrane damage is a c...
Free Radical Injury. A free radical is any molecule with an unpaired electron, including ROS and reactive nitrogen species (e.g....
Morphologic Appearance of Necrotic Cells and Tissues (Oncotic Necrosis). The appearance of necrotic cells depends on the type of...
Morphologic Appearance of Postmortem Changes
Chronic Cell Injury and Cell Adaptations
Cellular Survival during Sublethal Ischemia or Involution
Autophagy
Adaptations That Change Cell Size, Number, or Appearance
Atrophy
Hypertrophy
Hyperplasia
Metaplasia
Dysplasia
Intracellular Accumulations
Lipids
Glycogen
Proteins
Defects in Protein Folding. Newly synthesized proteins are moved into the ER lumen for folding and addition of disulfide bonds b...
Other Intracellular Inclusions
Autophagic Vacuoles. Autophagy (see previous section) is a response to injury in which cell membranes envelop portions of the cy...
Crystalline Protein Inclusions. Rhomboidal crystalline protein inclusions, also known as crystalloids (see Fig. 1.31, B), are co...
Viral Inclusion Bodies. Some types of viruses produce characteristic intranuclear or cytoplasmic inclusion bodies. Certain DNA v...
Lead Inclusions. In some cases of lead poisoning, intranuclear inclusions develop in renal tubular epithelial cells. The inclusi...
Extracellular Accumulations
Hyaline Substances
Amyloid. Increasingly diseases are attributed to the misfolding of soluble and functional peptides or proteins, converting them ...
Other Extracellular Accumulations
Fibrinoid Change. Fibrinoid change is the result of leakage of plasma proteins, such as immunoglobulin, complement, or fibrin, i...
Collagen (Fibrosis). Fibrosis is an excess in fibrous collagen, predominantly type I collagen, in the interstitium of organs or ...
Fatty Infiltration. Fatty infiltration is an increase in the number and/or volume of adipocytes in the interstitium of an organ ...
Gout
Pseudogout
Cholesterol. Cholesterol crystals are dissolved during histologic processing, leaving characteristic acicular (needle-shaped) cl...
Pathologic Calcification
Dystrophic Calcification
Metastatic Calcification
Heterotopic Ossification
Pigments
Exogenous Pigmented Substances
Carbon and Other Dusts. Coal mine dust lung disease, also known as black lung, is the best-studied example of pneumoconiosis (lu...
Carotenoid Pigments. Carotenoid pigments, such as β-carotene, are abundant in leafy green plants and impart a yellow coloration ...
Tetracycline. The antibiotic tetracycline binds to calcium phosphate in teeth and bones. If administered to animals during the t...
Nonhematogenous Endogenous Pigments
Melanin. Melanin is the pigment responsible for the color of the hair, skin, and iris. It also colors the leptomeninges in sheep...
Lipofuscin and Ceroid. Lipofuscin is a yellow-brown lipoprotein that accumulates as residual bodies in secondary lysosomes, espe...
Hematogenous Pigments
Hemoglobin. The hemoglobin molecule consists of four globular protein subunits, each folded around and tightly associated with a...
Hematin. Hematin is a brown-black, Fe+3-containing pigment formed by the oxidation of hemoglobin
Hemosiderin. Free iron is toxic to cells because it catalyzes the formation of ROS via the Fenton reaction. However, ferritin, a...
Hematoidin. Hematoidin is a bright-yellow crystalline pigment that is derived from hemosiderin, presumably within macrophages, b...
Bilirubin. Bilirubin is normally present in low amounts in the plasma as a breakdown product of erythrocytes (see Chapter 8, Hep...
Porphyria. Porphyrias are heme synthesis disorders that result in deposition of porphyrin pigments in tissues. The porphyrin rin...
Cell Cycle
Cellular Aging
Genetic Basis of Aging
Telomeres
Cellular Senescence
Structural and Biochemical Changes with Cellular Aging
Chromosome Structure and Function
Nuclear Chromosomes
Mitochondrial Chromosomes
Gene Structure and Function
Mechanisms of Genetic Disorders
Single-Gene Disorders
Single-Gene Disorders of Somatic Cells. Mutations that arise in somatic cells are not heritable but are important in the genesis...
Single-Gene Disorders of Germ Cells. Mutations that affect germ cells are transmitted to the progeny and can give rise to inheri...
Single-Gene Disorders of Mitochondria. Some single-gene disorders have a non-Mendelian pattern of inheritance and include disord...
Chromosomal Disorders
Errors in Cell Division. Most chromosomal disorders are caused by errors in cell division, which transfers the disorder within s...
Numeric Alterations. Cells with normal chromosome numbers have euploid karyotypes (i.e., normal number of chromosomes for the sp...
Structural Alterations. Changes in the structure of chromosomes are caused by deletion, inversion, duplication, or translocation...
Complex Multigenic Disorders
Components of Normal Cells and Their Vulnerabilities
Cell Membranes (Cytocavitary Network)
Second Messenger Systems. Cells are in continuous contact with a wide variety of extracellular molecules (see first messengers e...
Cytosol versus Cytoplasm
Nucleus
Nucleolus. The nucleolus (see Fig. 1.1) is a non–membrane-bound structure within the nucleus that forms around chromosomal loci ...
Rough Endoplasmic Reticulum
Ribosomes. Ribosomes facilitate the synthesis of proteins in cells (i.e., translation) (see Figs. 1.1 and 1.3). Their function i...
Golgi Complex
Smooth Endoplasmic Reticulum
Mitochondria
Oxidative Phosphorylation
Vaults
Lysosomes and Peroxisomes
Cytoskeleton: Microfilaments, Intermediate Filaments, and Microtubules
Cellular Inclusions
Intercellular Junctions and the Extracellular Matrix
2 - Vascular Disorders and Thrombosisa
Rete Mirabile (plural, Retia Mirabilia)
Microcirculation, Interstitium, and Cells
Interstitium and Extracellular Matrix (ECM)
Fluid Distribution and Homeostasis
Abnormal Fluid Distribution
Imbalance between Intracellular and Interstitial Compartments
Imbalance between Intravascular and Interstitial Compartments (Edema)
Mechanisms of Edema Formation
Increased Microvascular Permeability
Increased Intravascular Hydrostatic Pressure
Decreased Intravascular Osmotic Pressure
Decreased Lymphatic Drainage
Morphologic Characteristics of Edema
Hemostasis
Hemostatic Process
Primary Hemostasis
Secondary Hemostasis
Thrombolysis and Fibrinolysis
Regulation of Hemostasis
Coagulation Inhibitors
Fibrinolytic Inhibitors
Hemostasis and Other Host Responses
Disorders of Hemostasis: Hemorrhage and Thrombosis
Hemorrhage
Thrombosis
Normal Blood Flow, Distribution, and Perfusion
Alterations in Blood Flow and Perfusion
Increased Blood Flow
Decreased Blood Flow
Decreased Tissue Perfusion
Shock
Cardiogenic Shock
Hypovolemic Shock
Blood Maldistribution
Stages and Progression of Shock
Clinical and Morphologic Features of Shock
3 - Inflammation and Healinga
Beneficial and Harmful Aspects of Inflammation
Acute Inflammation
Substances Inducing the Acute Inflammatory Response
Fluidic (Exudative) Phase of the Acute Inflammatory Response
Endothelial Cell Dynamics during the Acute Inflammatory Response
Formation of Endothelial Cell Gaps
Cellular Phase of the Acute Inflammatory Response
Leukocyte Adhesion Cascade
Leukocyte Adhesion Deficiencies
Therapeutic Strategies to Modulate Leukocyte Infiltration
Additional Regulation of Inflammation
Inflammation and Pain
Effector Cells of the Acute Inflammatory Response
Neutrophils
Eosinophils
Basophils and Mast Cells
Lymphocytes
Natural Killer Cells and Natural Killer T Lymphocytes
Plasma Cells
Monocytes and Macrophages
Vascular Endothelial Cells
Chemical Mediators of the Acute Inflammatory Response
Complement Cascade
Arachidonic Acid Metabolites
Prostaglandin Formation and Inhibition
Leukotriene Formation and Inhibition
Omega-3 Fatty Acids (Fish Oils) and Inhibition of Eicosanoid Activity
Platelet-Activating Factor
Cytokine Family
Overview in Inflammation and Induction of CD4 TH Subsets
Cytokine Receptors and Signaling
Inflammatory Proteins
Interferons. Interferons are glycoprotein cytokines produced by lymphocytes and many other cell types in response to viruses and...
High Mobility Group Box Protein 1. High mobility group box protein 1 (HMGB-1) is a proinflammatory cytokine released by monocyte...
Chemokines
Classification of Chemokines
Chemokine Receptors and Signaling
Oxygen-Derived Free Radicals and Nitric Oxide
Receptors for Exogenous and Endogenous Inflammatory Stimuli and Toll-Like Receptors
Antimicrobial Peptides and Collectins
Acute Phase Proteins
Anti-inflammatory Mediators
Summary of the Chemical Mediators of Acute Inflammation
Reparative Phase of the Acute Inflammatory Response
Outcomes of the Acute Inflammatory Response
Nomenclature of the Inflammatory Response (Morphologic Diagnoses)
Morphologic Classification of Exudates in Acute Inflammatory Lesions
Serous Inflammation
Catarrhal Inflammation
Fibrinous Inflammation
Suppurative Inflammation
Chronic Inflammation
Beneficial and Harmful Aspects of Chronic Inflammation
Progression of the Acute Inflammatory Response to Chronic Inflammation, Fibrosis, and Abscess Formation
Progression to Chronic/Granulomatous Inflammation
Healing by Fibrosis
Abscess Formation
Granulomatous Inflammation and Granuloma Formation
Nodular (Tuberculoid) Granulomas (TH1-Biased Granulomas)
Diffuse (Lepromatous) Granulomas (TH2-Biased Granulomas)
Sarcoids of Horses
Eosinophilic Granulomas
Other Chronic Inflammatory/Granulomatous Conditions
Gross and Microscopic Lesions and Nomenclature of the Chronic Inflammatory Response
Effector Cells and Cellular Mechanisms of Chronic Inflammatory Responses
Lymphocytes
Innate Lymphoid Cells
γ/δ T Lymphocytes
α/β T Lymphocytes (CD4/CD8)
TH1, TH2, TH17, and T reg Immunologic Responses
Monocytes/Macrophages
Epithelium
Mononuclear Cell Maturation and Trafficking in the Chronic Inflammatory Response
Formation of Epithelioid Macrophages and Multinucleated Giant Cells (MGCs)
Dendritic Cells
Dendritic Cell Trafficking
B Lymphocytes
Plasma Cells
Eosinophils
Mast Cells
Natural Killer Cells and Natural Killer T Lymphocytes
Fibroblasts
Endothelial Cells
Platelets
Trafficking of Naïve and Activated T and B Lymphocytes
Homing of Naïve Lymphocytes via High Endothelial Venules
Adherence and Transendothelial Migration of Activated T Lymphocytes
Inflammation and the Sensation of Pain
The Effect of Inflammation on the Febrile Response and Other Activities
Unique Types of Inflammation
Septicemia and Endotoxic Shock
Septicemia
Septic (Endotoxic) Shock
Cytologic and Histologic Comparisons of Inflammatory Exudates
Wound Healing and Angiogenesis
First and Second Intention Healing
First Intention Healing
Second Intention Healing
Impaired Wound Healing
Expression of Genes Responsible for Wound Repair
Degradation of Cells and Tissue Components in Wounds
Degradation of the Extracellular Matrix (Interstitium) in Wounds
Resynthesis of the Extracellular Matrix (Interstitium) with Wound Healing
Synthesis of Collagen and Matrix Proteins
Collagen Production by Fibroblasts
Synthesis of Proteoglycans
Fibroblasts and the Mechanistic Basis of Fibrosis
Synthetic Matrices
Morphology of Granulation Tissue and Fibrous Connective Tissue
Granulation Tissue
Hypertrophic Scars. Hypertrophic scars occur as a result of exuberant proliferation of fibroblasts and collagen in wounds that f...
Fibrous Connective Tissue
Wound Contraction
The Scirrhous Reaction
Myofibroblasts. Myofibroblasts are specialized fibroblasts with contractile activity. They form within wounds in response to tis...
Angiogenesis in Wound Repair
Initiation of Endothelial Cell Proliferation
Endothelial Cell Growth Factors. The formation of new blood vessels in wounds begins from the proliferation of endothelial cell ...
Endothelial Cell Migration Is Mediated by Integrins. Newly formed endothelial cells and fibroblasts migrate into wound sites and...
Vascular Remodeling. Once blood vessels are initially formed, they are loosely arranged and require remodeling to become mature....
Regulators/Inhibitors of Endothelial Cell Growth. Inhibitors of angiogenesis are produced by endothelial cells, macrophages, and...
Epithelialization in Wound Repair
Intact Basement Membranes Enhance Reepithelialization
Initiation of Cell Proliferation in Epithelia
Senescent Cells
Differentiation of Epithelia
Remodeling
Metaplasia in Wound Repair
4 - Mechanisms of Microbial Infectionsa
Portals of Entry
Portal of Entry: Alimentary System (Ingestion)
Portal of Entry: Respiratory System (Inhalation)
Portal of Entry: Urogenital System (Ascending Infection)
Portal of Entry: Skin (Direct Contact and Cutaneous Penetration)
Portal of Entry: Ear and Eye (Direct Contact and Cutaneous Penetration)
Target Cells and Substances
Epithelial Cells as Microbial Targets
Mucosa-Associated Lymphoid Tissues as Microbial Targets
Biologic Substances as Microbial Targets
Pathways of Spread
Mechanisms Used to Colonize Mucosae (or Biologic Substances) at Portals of Entry
Colonize Mucus (Goblet Cells)
Colonize Cilia (or Microvilli) of Mucosal Epithelial Cells
Colonize the Cell (Endocytosis)
Mechanisms Used to Cross Mucosae at Portals of Entry
M Cell Entry
Transcytosis and Endocytosis/Exocytosis
Intercellular Direct Entry (Motility)
Non–M Cell Transcytosis Entry
Cell Polarity. In the alimentary and respiratory systems (and likely in other mucosae), the surface of an epithelial cell locate...
Dendritic Cell Entry
Leukocyte “Trojan Horse” Entry
Nerve Ending Entry
Mechanisms Used to Spread Systemically
Defense Mechanisms
Barrier Systems
Structural (Physical) Barriers
Functional (Biologic) Barriers
Mucus Layer. Mucosae of the alimentary and respiratory systems are covered by a protective mucous gel composed predominantly of ...
Immune System
Innate and Adaptive Immune Responses
Monocyte-Macrophage System
Dendritic Cells
Phagosome-Lysosome Fusion
Genetic Resistance of Animals to Infectious Diseases
Disorders of Barrier Systems
Disorders of the Innate Immune Response
Disorders of the Adaptive Immune Response
Bacterial Diseases
Morphology of Bacteria
Pathogenicity
Initial Encounters at Portals of Entry
Adhesion, Colonization, Invasiveness, and Toxigenesis
Adhesion, Colonization, and Invasiveness
Toxigenesis (Toxins)
Exotoxins and Lipoteichoic Acid. Exotoxins (usually from Gram-positive bacteria) are secreted from viable bacteria and are poten...
Endotoxins. Gram-negative bacteria, such as E. coli, Salmonella spp., Pseudomonas spp., Haemophilus spp., and Bordetella spp. ca...
Other Virulence Factors
Secretion Systems. Secretion systems, of which nine types (type I to IX; aka: T1SS–T9SS) have been described, are bacterial orga...
Siderophores. Some bacteria require iron for colonization of mucosae. Iron is plentiful in cells but unavailable to bacteria bec...
Biofilms/Intracellular Bacterial Communities. Bacterial coloni­zation can occur through virulence factors that form an exopolysa...
Capsules. Bacterial capsules are virulence factors that protect bacteria from phagocytosis by cells such as neutrophils and macr...
Role of Bacterial Genes in Susceptibility and/or Resistance to Disease
Virulence Factors
Antibiotic Resistance
Bacterial Gene Transfer
Vertical Gene Transfer. Vertical gene transfer is the process through which bacteria pass virulence factors such as antibiotic r...
Horizontal Gene Transfer. Bacteria can also transfer genes (e.g., antibiotic resistance genes) between variably related bacteria...
Mechanisms of Genomic Change
Bacterial Diseases of Organ Systems
Alimentary System and the Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
E-Table 4.3
E-Table 4.3
E-Table 4.3
Hepatobiliary System and Exocrine Pancreas
Respiratory System, Thoracic Cavities, Mediastinum, and Pleurae
Cardiovascular System and Lymphatic Vessels
Urinary System
Bone Marrow, Blood Cells, and Lymphoid/Lymphatic System
Nervous System
Skeletal Muscle
Bone, Joints, Tendons, and Ligaments
Integumentary System
Female Reproductive System and Mammae
Male Reproductive System
Viral Diseases
Morphology of Viruses
Target Cells
Viral Pathogenicity and Replication Cycle
Virulence Factors
Mechanisms of Genomic Change
Defense Mechanisms
Viral Diseases of Organ Systems
Alimentary System and the Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Hepatobiliary System and Exocrine Pancreas
Respiratory System, Thoracic Cavities, Mediastinum, and Pleurae
Cardiovascular System and Lymphatic Vessels
Bone Marrow, Blood Cells, and Lymphoid/Lymphatic System
Nervous System
Bone, Joints, Ligaments, and Tendons
Integumentary System
Female Reproductive System and Mammae
Male Reproductive System
The Eye
Fungal Diseases (Mycoses)
Morphology of Fungi
Fungal Diseases of Organ Systems
Respiratory System, Thoracic Cavities, Mediastinum, and Pleurae
Cardiovascular System and Lymphatic Vessels
Nervous System
Protozoan Diseases
Morphology of Protozoa
Protozoan Diseases of Organ Systems
Nervous System
Female Reproductive System and Mammae
Prion Diseases (Spongiform Encephalopathies)
Morphology of Prion Particles (Spongiform Encephalopathies)
Prion Diseases of Organ Systems
5 - Diseases of Immunitya
Innate Immunity (Nonspecific Immunity)
Recognition Molecules of Innate Immunity (Pathogen-Associated Molecular Patterns)
Toll-Like Receptors
Adaptive Immunity (Specific Immunity)
Cells and Tissues of the Immune System
Lymphoid Tissues
Innate Lymphoid Cells (ILCs)
T Lymphocytes
B Lymphocytes
Mononuclear Phagocytic System (Monocyte-Macrophage System)
Macrophages
Dendritic Cells
Natural Killer Cells
Cytokines: Messenger Molecules of the Immune System
General Properties of Cytokines
Structure and Function of Histocompatibility Antigens
Disorders of the Immune System
Mechanisms of Immunologic Tissue Injury: Hypersensitivity Reactions
Type I Hypersensitivity (Immediate Hypersensitivity)
Systemic Type I Hypersensitivity (Anaphylaxis). Anaphylaxis refers to an acute systemic hypersensitivity reaction to an antigen ...
Localized Type I Hypersensitivity. In a localized type I hypersensitivity reaction, the clinical signs and pathologic findings a...
Type II Hypersensitivity (Cytotoxic Hypersensitivity)
Type III Hypersensitivity (Immune Complex Hypersensitivity)
Localized Type III Hypersensitivity. Localized type III hypersensitivity reactions are best exemplified by the Arthus reaction (...
Generalized Type III Hypersensitivity. When antigen is present in the circulation at appropriate concentrations relative to circ...
Type IV Hypersensitivity (Delayed-Type Hypersensitivity)
Cytokine-Related Diseases
Transplant Rejection
General Features of Autoimmune Disease
Immunologic Tolerance
Mechanisms of Autoimmunity
Failure of Peripheral Tolerance
Genetic Factors in Autoimmunity
Central Tolerance. Central tolerance occurs during T lymphocyte development in the thymus, in which self-reactive T lymphocytes ...
Peripheral Tolerance. In peripheral tolerance, self-reactive T lymphocytes that are not eliminated as a result of negative selec...
Microbial Agents in Autoimmunity
Specific Autoimmune Diseases
Systemic Lupus Erythematosus
Etiology and Pathogenesis. The cause of SLE remains undetermined, although the presence of autoantibodies directed against a num...
Lesions of Systemic Lupus Erythematosus. A wide spectrum of morphologic lesions are associated with canine SLE. The most common ...
Genetic Factors. SLE in human beings is characterized as a disease with a complex genetic component with MHC and multiple non-MH...
Environmental Factors. In addition to the genetic factors, SLE in human beings has also been associated with a number of environ...
Immunologic Factors. As discussed previously, SLE is characterized by a number of immunologic abnormalities and is clinically no...
Rheumatoid Arthritis
Sjögren-Like Syndrome
Etiology and Pathogenesis. The keratoconjunctivitis sicca (dry eyes) and xerostomia (dry mouth) result from the lymphocytic infi...
Clinical Signs and Lesions. Dogs with Sjögren-like syndrome have an adult onset of conjunctivitis and keratitis. Other findings ...
Inflammatory Myopathies
Dermatomyositis. Dermatomyositis is an inflammatory disease of the skin, muscles, and vasculature affecting primarily young dogs...
Vasculitis
Clinical Signs and Immunologic Abnormalities. The classic presentation is a febrile (104° F to 107° F) young dog with anorexia, ...
Lesions. Severe necrotizing vasculitis and perivasculitis with thrombosis of small- to medium-sized blood vessels in the leptome...
Immunodeficiency Syndromes
Primary Immunodeficiencies
Primary Immunodeficiencies of Specific Immunity
Severe Combined Immunodeficiency Disease. Severe combined immunodeficiency disease (SCID) is a family of genetic defects that ha...
Common Variable Immunodeficiency. Common variable immunodeficiency is a primary immunodeficiency disease characterized by an adu...
Agammaglobulinemia. Agammaglobulinemia is a primary immunodeficiency characterized by an inability to produce immunoglobulins an...
Selective Immunoglobulin Deficiencies. Selective deficiencies are represented by several diseases characterized by a deficiency ...
Thymic Hypoplasia. Thymic hypoplasia represents several immunodeficiency diseases characterized by a failure to develop a functi...
Primary Immunodeficiencies of Nonspecific Immunity
Deficiencies of the Complement System. The complement system contains more than 30 soluble and cell-bound proteins that influenc...
Chédiak-Higashi Syndrome. Chédiak-Higashi syndrome is an inherited disease caused by defective lysosomes, melanosomes, platelet-...
Leukocyte Adhesion Deficiency. Leukocyte adhesion deficiency (LAD) is a primary immunodeficiency disease characterized by the in...
Immune Checkpoints in Immunity and Cancer
Amyloidosis
Pathogenesis of Amyloidosis
Chemical Nature of Amyloid
Classification of Amyloidosis
Primary Amyloidosis. Primary amyloidosis is the most common systemic form of amyloidosis in human beings and is of the AL type. ...
Reactive Systemic Amyloidosis. Reactive systemic amyloidosis is the most common form in animals. This form of amyloidosis has a ...
Familial Amyloidosis. Familial amyloidosis is a systemic form of AA amyloidosis that is hereditary in some breeds of cats and do...
Localized Amyloidosis. Occasionally, amyloid deposits are limited to a single organ or tissue. In many instances, the localized ...
Endocrine Amyloidosis. Deposition of amyloid in the pancreas of cats, nonhuman primates (macaques and baboons), and human beings...
Amyloid of Aging. Amyloid deposition can occur as an age-related change in a number of organ systems. Similar to senile systemic...
Morphology of Amyloidosis
6 - Neoplasia and Tumor Biologya
Tumor Characteristics (Essential Concept 6.1)
Benign Versus Malignant Tumors
Differentiation of Tumors
Gross Patterns of Tumor Growth
Microscopic Tumor Morphology
Tumor Cell Function
Differentiation Therapy
Tumor Cell Proliferation and Death
Tumor Growth
Cell Division
Cell Senescence and Death
Senescence. Senescent cells are somatic cells that can no longer divide; these cells stop dividing through a mechanism called re...
Apoptosis. Apoptosis is a form of “programmed cell death” that serves both as a normal physiologic process and as a response to ...
Autophagy. Autophagy refers to degradation of a cell’s own organelles within autophagosomes (see Fig. 1.24). Autophagy can be a ...
Neoplastic Transformation (Essential Concept 6.2)
Latency
Stepwise Tumor Development
Initiation
Promotion
Progression
Tumor Heterogeneity and Clonal Selection
Stem Cells and Cancer
Tumor Microenvironment (Essential Concept 6.3)
Tumor Stroma
Composition of the Stroma
Tumor-Stromal Interactions
Angiogenesis
Inflammation
Tumor Immunity (see Essential Concept 6.3)
Immunosurveillance
Tumor Antigens
Antitumor Effector Mechanisms
Natural Killer Cells
Macrophages
T Lymphocytes
B Lymphocytes
Evasion of the Immune Response
Altered Major Histocompatibility Complex Expression
Antigen Masking
Tolerance
Immunosuppression
Tumor Immunotherapy
Tumor Dissemination (Essential Concept 6.4)
Significance of Tumor Metastasis
Mechanisms of Tumor Invasion and Metastasis
Adhesion
Migration
Stromal Invasion
Epithelial-Mesenchymal Transition
Intravasation
Tumor Emboli
Extravasation
Pathways of Tumor Spread
Lymphatic Spread
Hematogenous Spread
Transcoelomic Spread
Transmissible Tumors
Metastasis Suppression
Systemic Clinical Effects on the Animal (see Essential Concept 6.3)
Direct Effects
Paraneoplastic Effects
Cachexia
Endocrinopathies
Endocrine Tumors. A functioning endocrine tumor produces the hormonal products of the tissue of origin. For example, thyroid fol...
Nonendocrine Tumors. A variety of nonendocrine neoplasms may also produce hormonally active substances not normally found in the...
Skeletal Syndromes
Vascular and Hematologic Syndromes
Additional Neoplastic Syndromes
Neurologic Syndromes. Paraneoplastic neurologic disease in veterinary cancer patients is usually related to hypercalcemia, hypog...
Cutaneous Syndromes. There are only a few reports of cutaneous manifestations of paraneoplastic disease in dogs and cats. Clinic...
Miscellaneous Syndromes. Mast cell tumors are very common in dogs. Release of excess histamine from the neoplastic mast cells ca...
Heritable Alterations in Cancer (Essential Concept 6.5)
Genetic Changes in Cancer
Point Mutations
DNA Strand Breaks
Insertions and Deletions
Amplifications
Aneuploidy
Chromosomal Instability
Germline Mutations and Cancer Syndromes
Acquired Somatic Mutations and Sporadic Cancers
Epigenetic Changes in Cancer
DNA Methylation
Histone Modification
Imprinting
Noncoding RNAs and Cancer
Molecular Determinants of Cancer
Oncogenes
Tumor Suppressor Genes
Modifier Genes
Defects in DNA Repair
Multistage Carcinogenesis
Therapeutic Implications
Mechanisms of Carcinogenesis
Intrinsic Factors
Extrinsic Factors
Chemicals
Radiation
Viruses
Dominant Oncogene Mechanism. The genomes of many rapidly transforming oncogenic viruses include a dominant oncogene that drives ...
Insertional Mutagenesis Mechanism. Viruses that do not carry their own oncogenes can instead activate the expression of oncogene...
Hit-and-Run Mechanism. In the two mechanisms discussed previously, the viral genome or portions of it persist in the infected ce...
Indirect Mechanisms. Viruses may also stimulate tumorigenesis by suppression of the animal’s immune system or by stimulation of ...
Cancer in Animals
Naturally Occurring Tumors
Animal Models of Cancer
Experimentally Induced Tumors in Laboratory Animals
Tumor Diagnosis and Prognosis
Cytologic Tumor Diagnosis
Limitations of Cytology. Cytology samples are generally easy to collect and often provide useful information to the clinician, b...
Cytologic Evaluation of Malignant Potential. As tissue architecture cannot be assessed cytologically, cytologic estimation of th...
Cytologic Categories of Neoplasia. As with histopathology, neoplastic cells are categorized as epithelial, mesenchymal, or round...
Cytomorphology and Histomorphology of Selected Neoplasms. The goal of this section is to compare and illustrate the morphologic ...
Histopathologic Tumor Diagnosis
Sample Collection for Histopathologic Tumor Evaluation. For optimal sample quality, regions of inflammation, hemorrhage, necrosi...
Histopathologic Evaluation of Tumors. Biopsy specimens undergo extensive processing; ultimately a 3- to 5-μm thick section of ti...
Surgical Margin Evaluation
Grading
Staging
Miscellaneous Techniques in Tumor Diagnosis
Clonality Assays. Sometimes it is difficult to distinguish benign lymphoid hyperplasia from lymphoma by morphologic features alo...
Flow Cytometry. Flow cytometry is a method available through many academic or commercial veterinary diagnostic laboratories that...
Cytogenetic Analysis. Cytogenetic analysis can be a useful tool for diagnosis, determining the presence of residual disease afte...
Pedigree Analysis. Identification of genes involved in inherited cancers can be accomplished through the detailed analysis of we...
Molecular Diagnostic Techniques. Recently, developed techniques permit global gene expression analysis of tumors. Microarrays, w...
Neoplasia
Preneoplastic Changes
Tumor Types: Cell of Origin
Mesenchymal Tumors
Epithelial Tumors
Tumors of Neural Crest Cells
Tumors of Uncertain Origin
Mixed Tumors
Tumor-Like Lesions
Tumor Nomenclature
II - Pathology of Organ Systems
7 - Alimentary System and the Peritoneum, Omentum, Mesentery, and Peritoneal Cavitya
Dysfunction/Responses to Injury
Oral Cavity
Teeth
Tonsils
Salivary Glands
Tongue
Esophagus
Rumen, Reticulum, and Omasum
Stomach and Abomasum
Intestine
Inflammation
Necrotizing Processes
Lymphangiectasia
Disorders of Innervation
Diarrhea
Consequences of Diarrhea. Normal feces are composed of 75% water, while diarrheal feces are composed of greater than 85% water. ...
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Ascites
Fat Necrosis
Inflammation: Peritonitis
Parasitic Peritonitis. Aberrant migration of nematodes and trematodes in most species of animals can cause focal fibrosis in per...
Pneumoperitoneum
Gastrointestinal Aging
Portals of Entry/Pathways of Spread
Oral Cavity
Teeth
Tonsils
Salivary Glands
Tongue
Esophagus
Rumen, Reticulum, and Omasum
Stomach and Abomasum
Intestine
Targets for Microbial Colonization or Destruction of Intestinal Mucosae
Disorders of the Intestinal Epithelium
Disorders of the Absorptive Enterocytes. A number of agents have a tropism for the absorptive cells lining the intestinal villi....
Disorders of Undifferentiated Crypt Cells. Loss of the undifferentiated epithelial cells in the base of the crypts means loss of...
Abnormalities of the Microvilli and Glycocalyx. Because the microvilli and glycocalyx on villous enterocytes are largely respons...
Disorders in Which the Epithelial Targets Are Unknown or Nonspecific. In a number of enteric diseases, the targeted epithelial c...
Separation of Apical Junctional Complexes. Apical junctional complexes, also called tight junctions or zona occludens, join ente...
Disorders of the Lamina Propria
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Defense Mechanisms/Barrier Systems
Oral Cavity
Teeth
Tonsils
Salivary Glands
Tongue
Esophagus
Rumen, Reticulum, and Omasum
Stomach and Abomasum
Intestine
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Oral Cavity
Developmental Anomalies
Stomatitis and Gingivitis
E-Appendix 7.1 Necropsy Techniques
Vesicular Stomatitides: Viral Diseases
Vesicular Stomatitis. Vesicular stomatitis is common in calves, pigs, and some wildlife species but does not occur in sheep or g...
Other Vesicular Stomatitides. Vesicular exanthema is a specific disease of pigs that is indistinguishable clinically and patholo...
Erosive and Ulcerative Stomatitides
Necrotizing Stomatitides
Eosinophilic Stomatitides
Lymphoplasmacytic Stomatitis
Chronic Ulcerative Paradental Stomatitis
Oral Mucosal Hyperplasia and Neoplasia
Hyperplastic and Neoplastic Disorders of the Gums and Teeth. Gingival hyperplasia is a simple overgrowth of gum tissue, principa...
Neoplasia. In the dog, 70% of tumors of the alimentary system are found in the oral cavity and oropharynx. These tumors run the ...
Teeth
Malocclusions
Anomalies of Tooth Development
Lesions Caused by Attrition and Abnormal Wear
Miscellaneous Dental Disorders
Infundibular Impaction. Impaction of the infundibulum, also known as infundibular necrosis or infundibular caries, may cause ser...
Periodontal Disease. More than 200 species of bacteria and fungi have been associated with dental plaque (a film composed of an ...
Dental Neoplasia
Tonsils
Salivary Glands
Inflammatory Disorders
Miscellaneous Disorders
Neoplasia
Tongue
Developmental Anomalies
Systemic Disease: Involvement of the Tongue
Primary Involvement. Disease agents that principally target the tongue are relatively rare. The exception to this rule is Actino...
Secondary Involvement. Thrush is a Candida albicans (yeast) infection of intact mucous membranes of the tongue and esophagus (se...
Hyperplastic and Neoplastic Conditions
Parasites
Esophagus
Achalasia. Esophageal motility disorders are termed achalasia. In this condition, the sequential contractility of the esophagus ...
Megaesophagus
Hiatal Hernia
Esophageal Parasites
Miscellaneous Esophageal Disorders
Choke
Neoplasia
Rumen, Reticulum, and Omasum
Stomach and Abomasum
Gastric Dilation and Volvulus
Abomasal Displacement
Gastric Dilation and Rupture
Abomasal Dilation and Tympany
Impaction
Inflammatory Disorders
Hypertrophic/Hyperplastic Gastritis
Ulcers: Mucosal Defects
Miscellaneous Disorders
Neoplasia
Intestine
Atresia. Occlusion of the intestinal lumen as the result of anomalous development of the intestinal wall is called atresia (Fig....
Meckel’s Diverticulum. Meckel’s diverticulum is a remnant of the omphalomesenteric duct. Generally, it disappears after the firs...
Megacolon. Megacolon, as its name implies, is a large, usually feces-filled colon (Figs. 7.95 and 7.96) that can be congenital o...
Intestinal Obstruction
Enteroliths and Impaction. Enteroliths are rare in species other than horses and camelids. In horses, Arabians have an increased...
Strictures with Obstruction. Strictures are the result of narrowing of the lumen of a canal, which in the present case is the in...
Intussusception. When one segment of intestine becomes telescoped into the immediately distal segment of intestine, the lesion i...
Ileus. Paralytic ileus (adynamic ileus) is a nonmechanical hypomotility resulting in a functional obstruction of the bowel (pseu...
Intestinal Displacements
Volvulus and Torsion. A volvulus is a twisting of the intestine on its mesenteric axis (a twist around an axis perpendicular to ...
Miscellaneous Disorders
Small Intestinal Intoxicants
Vascular Disorders of the Intestine
Lymphangiectasia. Lymphangiectasia (i.e., pathologic dilation of lymphatic vessels see Figs. 7.13 and 7.14) may be congenital as...
Innervation Disorders of the Intestine
Disorders Caused by Specific Pathogens
Parasitic Diseases. Parasites of the intestinal tract are legion in the various domestic animal species. Refer to a parasitology...
Intestinal Neoplasia
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Parasitic Diseases
Neoplasia
Primary Neoplasms. Primary neoplasms of the peritoneum are uncommon, with the exception of lipomas, which may become pedunculate...
Secondary Neoplasms. Hemangiosarcoma is a malignant neoplasm of endothelial cells and is a common primary tumor of the spleen, e...
Diseases of Horses
Teeth
Equine Odontoclastic Tooth Resorption and Hypercementosis
Salivary Glands
Intestine
Renosplenic Entrapment. Renosplenic entrapment of the large colon in horses is due to left dorsal displacement of the left dorsa...
Right Dorsal Displacement. In the equine condition right dorsal displacement, the left dorsal and ventral colons are displaced t...
Bacterial Diseases
Rhodococcus equi Enteritis. R. equi is a soil saprophyte and a normal inhabitant of the equine intestine. The disease caused by ...
Parasitic Diseases
Equine Bots. Equine bots, Gasterophilus intestinalis and Gasterophilus nasalis, are commonly seen in animals on inadequate dewor...
Draschia. Draschia megastoma is found in “brood pouches” in the glandular mucosa adjacent to the margo plicatus (Fig. 7.141). In...
Cyathostomiasis. In ponies and horses under 5 years of age in temperate climates, sudden emergence of massive numbers of fourth-...
Rickettsial Diseases
Equine Monocytic Ehrlichiosis. Equine monocytic ehrlichiosis, also known as Potomac horse fever, was first reported in 1983. It ...
Idiopathic Disorders
Equine Granulomatous Enteritis. Equine granulomatous enteritis is characterized by wasting and hypoalbuminemia and has been repo...
Clostridial Enteritis (Colitis X). The severe diarrhea seen in cases of colitis X is generally nonhemorrhagic and is rapidly fat...
Hemorrhagic Fibrinonecrotic Duodenitis–Proximal Jejunitis. In hemorrhagic fibrinonecrotic duodenitis–proximal jejunitis, also kn...
Chronic Eosinophilic Gastroenteritis and Multisystemic Eosinophilic Epitheliotropic Disease. Soft stools accompanied by weight l...
Idiopathic Focal Eosinophilic Enteritis. Idiopathic focal eosinophilic enteritis is characterized by infiltration of eosinophils...
Cranial Cecal Impaction. In this uncommon condition, impaction of cecal cupula (cecal base) occurs without other cecal or intest...
Anaphylactoid Purpura. Leukocytoclastic vasculitis associated with numerous discrete foci of necrosis and hemorrhage throughout ...
Vascular Disorders of the Intestine
Strongylus vulgaris. In horses Strongylus vulgaris fourth-stage larvae are present in the wall of the cranial mesenteric artery,...
Diseases of Ruminants (Cattle, Sheep, and Goats)
Oral Cavity
Foot-and-Mouth Disease. Foot-and-mouth disease is an extremely important disease of artiodactyls worldwide but has not appeared ...
Parapox Stomatitides. The two major diseases in this category, bovine papular stomatitis and contagious ecthyma, are zoonotic. B...
Rumen, Reticulum, and Omasum
Bloat (Ruminal Tympany)
Foreign Bodies
Inflammatory Disorders
Miscellaneous Disorders
Vagal Indigestion
Ruminal Parasitism
Abomasum
Abomasal Displacement
Abomasal Dilation and Tympany
Intestine
Bovine Viral Diarrhea. Bovine viral diarrhea, also known as mucosal disease, affects cattle of all ages but is most common in an...
Rinderpest. Lesions similar to those of bovine viral diarrhea occur in cattle with rinderpest. The morbillivirus associated with...
Peste des Petits Ruminants. Peste des petits ruminants is a distinct morbillivirus disease of sheep and goats that causes ulcera...
Border Disease. The pestivirus causing border disease in sheep and goats is antigenically related to the noncytopathic biotype o...
Malignant Catarrhal Fever. Malignant catarrhal fever, which is caused by closely related rhadinoviruses (γ-herpesviruses), occur...
Winter Dysentery. Winter dysentery is a somewhat enigmatic, acute, generally nonfatal disease of adult cattle. Although its caus...
Bovine Torovirus Diarrhea. The shedding of bovine torovirus (BoTV), or Breda virus, has been associated with diarrhea of neonata...
Coronavirus Colitis of Beef Calves. Recently a hemorrhagic and sometimes fatal colitis was reported from postweaning beef calves...
Bacterial Diseases
Clostridium perfringens Type B. C. perfringens type B is the cause of lamb dysentery. This is generally a disease of very young ...
Clostridium perfringens Type D. C. perfringens type D affects fattening sheep, goats, and calves. The disease is diet related an...
Paratuberculosis (Johne’s Disease). Paratuberculosis, or Johne’s disease, has been described in numerous ruminant species and is...
Hemorrhagic Bowel Syndrome of Dairy Cattle. Hemorrhagic bowel syndrome, also known as fatal jejunal hemorrhage syndrome, intralu...
Chlamydial Diseases
Chlamydiosis. Bovine chlamydia (Chlamydophila pecorum) has been recovered from spontaneous enteritis of young calves. After expe...
Parasitic Diseases
Haemonchus contortus. Haemonchus contortus, known as the “barber’s pole worm,” is relatively common in small ruminant and New Wo...
Ostertagiasis. In temperate climates, ostertagiasis is considered the most important parasitic disease in cattle (Ostertagia ost...
Coccidiosis. Abomasal coccidiosis has been reported in a sheep. Mucosal lesions are nodular and hemorrhagic with hyperplasia of ...
Trichostrongylosis. Trichostrongyles are small nematodes that parasitize the small intestine of ruminants. Mild climates promote...
Nematodirosis. Nematodirus nematodes are parasites of the cranial small intestine of ruminants. The life cycle is direct. Unlike...
Cooperiasis. A small intestinal parasite of ruminants, Cooperia nematodes—unlike other trichostrongyles—do not burrow into the i...
Oesophagostomum. The nodular worms of ruminants (Oesophagostomum columbianum, Oesophagostomum radiatum) and pigs (Oesophagostomu...
Intestinal Neoplasia
Diseases of Pigs
Tonsils
Pseudorabies (Aujeszky’s Disease)
Tongue
Stomach
Intestine
Viral Diseases
Transmissible Gastroenteritis. Transmissible gastroenteritis (TGE) is an important disease in pigs younger than 10 days. Older a...
Porcine Epidemic Diarrhea. Porcine epidemic diarrhea virus (PEDV) was first recognized in China in 2010 and rapidly spread world...
Porcine Circovirus Enteritis. Porcine circovirus (PCV) is ubiquitous in pigs worldwide. The small, single-stranded, nonenveloped...
Bacterial Diseases
Edema Disease. Edema disease, also known as enterotoxemic colibacillosis, is an E. coli (F18ab) infection that is specific for p...
Postweaning Colibacillosis. Postweaning colibacillosis is another specific disease of pigs caused by a hemolytic E. coli. The di...
Swine Dysentery. Unlike most of the other diseases of the porcine gut, swine dysentery is generally confined to the large intest...
Lawsonia Enteritis. Lawsonia enteritis manifests in a variety of ways, as indicated by the number of names applied to it: prolif...
Chlamydial Diseases
Chlamydiosis. Chlamydia has been found in enterocytes of normal pigs and pigs with diarrhea. In gnotobiotic pigs, Chlamydia trac...
Parasitic Diseases
Balantidiasis (Balantidium coli). Balantidium coli is a normal amoebic inhabitant of the cecum and colon of primates, including ...
Hyostrongylus rubidus. Hyostrongylus rubidus of pigs is a gastric parasite that causes a thickening of the mucosa, with mucus ac...
Miscellaneous Disorders
Intestinal Emphysema. Intestinal emphysema (pneumatosis cystoides intestinalis) of pigs and rabbits translates to gas-dilated ly...
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Glasser’s Disease
Diseases of Dogs
Stomach
Parasitic Diseases
Intestine
Lymphangiectasia
Viral Diseases
Parvovirus Enteritis. Parvovirus enteritis of dogs (and cats) is a severe, usually fatal disease. Because the target cells are t...
Circovirus. Canine circovirus (dog CV) is associated with vomiting, hematochezia, hemorrhagic gastroenteritis, necrotizing vascu...
Minute Virus of Dogs. Canine parvovirus type 1 produces myocarditis and respiratory disease in young pups. The virus is widely d...
Bacterial Diseases
Histiocytic Ulcerative Colitis. Because of its occurrence in boxer dogs and the genetically related French bulldog, histiocytic ...
Citrobacter freundii Enteritis. Bacteremia and septicemia associated with Citrobacter freundii have been reported to cause mucoh...
Fungal Diseases
Canine Pythiosis. Pythium insidiosum is an aquatic oomycete that is more closely related to algae than fungi, but because of its...
Canine Histoplasmosis. Canine histoplasmosis occurs most often in the Ohio and Mississippi River valleys. This zoonotic systemic...
Rickettsial Diseases
Salmon Poisoning. Salmon poisoning is an acute and fatal hemorrhagic granulomatous enterocolitis of the dog and fox that results...
Parasitic Diseases
Canine Multifocal Eosinophilic Gastroenteritis. Canine multifocal eosinophilic gastroenteritis is an uncommon disease of dogs ge...
Immunologic Disorders
Inflammatory Bowel Disease. In dogs and cats, inflammatory bowel disease is microscopically a lymphoplasmacytic to eosinophilic ...
Diffuse Eosinophilic Gastroenteritis. Although diffuse eosinophilic gastroenteritis has a predilection for the German shepherd b...
Wheat-Sensitive Enteropathy of Irish Setters. Wheat-sensitive enteropathy, a hereditable condition similar to gluten-sensitive e...
Idiopathic Disorders
Canine Senile Gastrointestinal Amyloidosis. Amyloid located in and around vessels of the submucosal and muscular layers of the a...
Sclerosing Encapsulating Peritonitis
Diseases of Cats
Oral Cavity
Eosinophilic Stomatitides
Teeth
Feline External Resorptive Neck Lesions
Stomach
Parasitic Diseases
Intestine
Immunologic Disorders
Feline Ulcerative Colitis. Feline ulcerative colitis is grossly and histologically analogous to its canine counterpart, histiocy...
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Teeth
Tonsils
Salivary Glands
Tongue
Esophagus
Rumen, Reticulum, and Omasum
Stomach and Abomasum
Intestine
Epithelial Cells
Mesenchymal Cells
Peritoneum, Omentum, Mesentery, and Peritoneal Cavity
Pacinian Corpuscles
8 - Hepatobiliary System and Exocrine Pancreasa
E-Appendix 8.1 Postmortem Evaluation of the Liver and Biliary System
Embryologic Development
Function
Production and Excretion of Bile
Bilirubin Metabolism
Carbohydrate Metabolism
Lipid Metabolism
Xenobiotic Metabolism
Protein and Urea Synthesis
Immune Function
Dysfunction/Responses to Injury
Oncotic Necrosis and Apoptosis
Patterns of Hepatocellular Degeneration and/or Necrosis. Although the liver is subjected to a wide variety of different insults,...
Morphologic Classification of Hepatobiliary Disease
Acute Hepatitis. Inflammation of the liver parenchyma is termed hepatitis. Acute hepatitis is characterized by inflammation, hep...
Chronic Hepatitis. Chronic hepatitis results when there is continued inflammation as a result of persistence of an antigenic sti...
Interface Hepatitis (Piecemeal Necrosis). Interface hepatitis, also called piecemeal necrosis, is characterized by inflammation ...
Nonspecific Reactive Hepatitis. Nonspecific reactive hepatitis is a multifocal or diffuse process distributed throughout the liv...
Cholangitis. Inflammation of the biliary ducts (either intrahepatic or extrahepatic) is termed cholangitis. There are several pa...
Cholangiohepatitis. Inflammation that affects both the biliary ducts and hepatic parenchyma is termed cholangiohepatitis. In mos...
Disturbances of Bile Flow and Icterus
Ductular Reaction (Biliary Hyperplasia)
Regeneration
Fibrosis
End-Stage Liver or Cirrhosis
Hepatic Failure
Hepatic Encephalopathy. Hepatic failure or portosystemic shunts can result in a metabolic disorder of the central nervous system...
Metabolic Disturbances of Hepatic Failure. Hepatic failure can be manifested by a variety of metabolic disturbances, including b...
Vascular and Hemodynamic Alterations of Hepatic Failure. Chronic hepatic injury typically is accompanied by extensive diffuse fi...
Immunologic Manifestations of Hepatic Failure. Chronic liver failure leads to an impairment of normal hepatic immune function an...
Aging
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Developmental Anomalies and Incidental Findings
Hepatic Displacement. Displacement of the liver into the thoracic cavity, called a diaphragmatic hernia, can occur when there is...
Tension Lipidosis (Steatosis). Discrete, pale areas of parenchyma at the liver margins are common in cattle and horses (Fig. 8.3...
Capsular Fibrosis. Discrete fibrous tags or plaques are frequently present on the diaphragmatic surface of the liver and on the ...
Circulatory Disorders
Metabolic Disturbances and Hepatic Accumulations
Hepatocellular Steatosis (Lipidosis). Lipids are normally transported to the liver from adipose tissue and the gastrointestinal ...
Glycogen Accumulation. Glucose is normally stored within hepatocytes as glycogen and is often present in large amounts after fee...
Lysosomal Storage Diseases. Vacuolation of hepatocytes and Kupffer cells can be observed in several types of lysosomal storage d...
Amyloidosis. Hepatic amyloidosis occurs in most species of domestic animals. Amyloidosis is not a single disease entity but rath...
Copper Accumulation. Copper toxicosis is included as a metabolic disorder because hepatic injury in copper poisoning of domestic...
Pigment Accumulation. Pigments are colored substances, some of which are normal cellular constituents, whereas others accumulate...
Infectious Diseases of the Liver
Protozoal Diseases. The liver can be involved in systemic infections with Toxoplasma gondii, Neospora sp., and other less common...
Fungal Diseases. Fungal infection can become disseminated and affect a variety of visceral organs, including the liver. Systemic...
Anchor 1410
Toxicant-Induced Liver Disease
Hepatic Injury as a Consequence of Systemic Disease
Proliferative Lesions of the Liver
Hepatocellular Nodular Hyperplasia. Hepatocellular nodular hyperplasia is common only in the dog. The incidence increases with a...
Regenerative Nodules. Regenerative nodules are another type of nodular hepatocellular lesion. Unlike nodular hyperplasia, regene...
Hepatic Neoplasia. Primary neoplasms of the hepatobiliary system can arise from epithelial elements, including hepatocytes, bili...
Carcinoids. Carcinoids, also called neuroendocrine carcinomas, are uncommon tumors that arise from neuroendocrine cells that lie...
Miscellaneous Primary Mesenchymal Neoplasms of the Liver. Primary neoplasms can arise from any of the cellular constituents of t...
Metastatic Neoplasms. The liver and the lung are the two most common sites for metastatic spread of malignant neoplasms. Metasta...
Hepatosplenic and Hepatocytotropic T Cell Lymphoma. Two distinct types of T cell lymphoma, described mainly in dogs, involve the...
Diseases of Horses
Equine Serum Hepatitis
Equine Hepatocellular Steatosis
Diseases of Ruminants (Cattle, Sheep, and Goats)
Ketosis
Bovine Fatty Liver Syndrome
Copper Toxicosis
Rift Valley Fever
Wesselsbron Disease
Bacillary Hemoglobinuria
Infectious Necrotic Hepatitis
White Liver Disease
Diseases of Pigs
Hepatosis Dietetica
Cresols
Diseases of Dogs
Canine Chronic Hepatitis
Lobular Dissecting Hepatitis
Copper-Associated Chronic Hepatitis
Glucocorticoid-Induced Hepatocellular Degeneration (Steroid Hepatopathy)
Infectious Canine Hepatitis
Canine Hepatocerebellar Degeneration Syndrome
Diseases of Cats
Feline Fatty Liver Syndrome
Lymphocytic Cholangitis
Neutrophilic (Suppurative) Cholangitis
Gallbladder and Extrahepatic Bile Ducts
Embryologic Development
Function
E-Appendix 8.2 Postmortem Evaluation of the Exocrine Pancreas
Dysfunction/Responses to Injury
Aging
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Developmental Abnormalities
Congenital Biliary Cysts
Cholelithiasis
Cholecystitis
Hyperplastic and Neoplastic Lesions
Cystic Mucinous Hyperplasia of the Gallbladder. Cystic mucinous hyperplasia of the gallbladder mucosa has only been reported in ...
Neoplasms. Biliary neoplasms (i.e., cholangiocellular adenoma and cholangiocellular carcinoma) have been described previously in...
Diseases of Horses
Diseases of Ruminants (Cattle, Sheep, and Goats)
Salmonella Infection
Diseases of Pigs
Mulberry Heart Disease
African Swine Fever
Diseases of Dogs
Thrombosis and Infarction of the Gallbladder
Gallbladder Mucocele
Infectious Canine Hepatitis
Diseases of Cats
Exocrine Pancreas
Embryologic Development
Function
Dysfunction/Responses to Injury
Aging
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Anomalies of the Duct System. The arrangement of the major pancreatic duct and accessory ducts varies between and within species...
Ectopic Pancreatic Tissue. Nodules of ectopic pancreatic tissue sometimes are present in the duodenum or other sections of the s...
Ectopic Splenic Tissue. Nodules of ectopic splenic tissue have been reported in the pancreas of dogs and cats (see Fig. 13.81). ...
Pacinian Corpuscles. Pacinian corpuscles are normally present within the interlobular connective tissue of the pancreas and mese...
Pancreatic Calculi. The formation of concretions or “stones” within the pancreatic duct system is termed pancreatolithiasis and ...
Pancreatic Lipomatosis (Fatty Infiltration). Fat cell infiltration of the interstitial connective tissue of the pancreas occurs ...
Pancreatic Pseudocysts. Pancreatic pseudocysts are fluid-filled nonepithelialized fibrous sacs containing cellular debris, blood...
Pancreatic Cysts. Congenital cysts can occasionally be observed in the pancreas and are believed to result from cystic dilatatio...
Pancreatitis/Pancreatic Necrosis
Pathogenesis of Pancreatitis. The three major proposed mechanisms of pancreatitis are as follows (Fig. 8.89)
Acute Pancreatitis. Acute pancreatitis occurs most often in dogs and occasionally in cats. It is uncommon in other domestic spec...
Chronic Pancreatitis. Chronic pancreatitis is typically accompanied by fibrosis and parenchymal atrophy. It can occur in all spe...
Pancreatic Degeneration and Atrophy
Lysosomal Storage Diseases
Parasitic Infections
Hyperplasia and Neoplasia
Pancreatic Nodular Hyperplasia. Nodular hyperplasia of the exocrine pancreas occurs in dogs, cats, and cattle. It is especially ...
Pancreatic Adenoma. Adenomas of the exocrine pancreas are extremely rare but have been described in dogs, cats, and cattle. They...
Pancreatic Carcinoma. Carcinoma of the ductular epithelium or acinar cells of the exocrine pancreas is uncommon in all species. ...
Diseases of Horses
Diseases of Ruminants (Cattle, Sheep, and Goats)
Pancreatic Hypoplasia
Diseases of Pigs
Diseases of Dogs
Exocrine Pancreatic Atrophy (Juvenile Pancreatic Atrophy)
Diseases of Cats
9 - Respiratory System, Thoracic Cavities, Mediastinum, and Pleuraea
Dysfunction/Responses to Injury
Vulnerability of the Structural Components of the Respiratory System
Respiratory System: Conducting Component
Nose, Paranasal Sinuses, Larynx, and Trachea
Bronchi
Respiratory System: Transitional Component
Bronchioles
Local Production of Free Radicals and Toxic Metabolites. The lungs, particularly the bronchioles and alveoli, are vulnerable to ...
Respiratory System: Air Exchange Component
Alveoli
Aging Changes of the Respiratory System
Thoracic Cavities, Mediastinum, and Pleurae
Portals of Entry/Pathways of Spread
Respiratory System
Aerogenous
Hematogenous
Direct Extension
Pathways of Spread from the Respiratory System (Locally, Regionally, and Systemically)
Thoracic Cavities, Mediastinum, and Pleurae
Hematogenous
Direct Extension
Defense Mechanisms/Barrier Systems
Respiratory System
Mucociliary Clearance. Mucociliary clearance is the physical unidirectional movement and removal of deposited particles and gase...
Microfold (M) Cells. In addition to the mechanical barrier and physical transport provided by the mucociliary escalator, other c...
Air Exchange Component
Defense Mechanisms against Specific Types of Injury
Aerogenous Injury. It is axiomatic that a particle, microbe, or toxic gas must first gain entry to a vulnerable region of the re...
Hematogenous (Bloodborne) Injury. Lungs are also susceptible to hematogenously borne microbes, toxins, or emboli. The hepatic (K...
Injury from Oxidants and Free Radicals. Existing in an oxygen-rich environment and being the site of numerous metabolic reaction...
Impairment of Defense Mechanisms in the Respiratory System
Impairment Caused by Viral Infections. Viral agents are notorious in predisposing human beings and animals to secondary bacteria...
Impairment Caused by Toxic Gases. Certain gases also impair respiratory defense mechanisms, rendering animals more susceptible t...
Impairment Caused by Immunodeficiencies. Immunodeficiency disorders, whether acquired or congenital, are often associated with i...
Other Conditions That Impair Defense Mechanisms. Stress, uremia, endotoxemia, dehydration, starvation, hypoxia, acidosis, pulmon...
Thoracic Cavities, Mediastinum, and Pleurae
Respiratory System: Conducting Component
Metabolic Disorders. Metabolic disturbances affecting the nasal cavity and sinuses are rare in domestic animals
E-Appendix 9.1 Postmortem Examination of the Respiratory System
E-Appendix 9.2 Histopathology and Biopsies
E-Appendix 9.3 Bronchoalveolar Lavage and Transtracheal Wash
Inflammation (Rhinitis and Sinusitis). Inflammation of the nasal mucosa is called rhinitis, and inflammation of the sinuses is c...
Neoplasms. Neoplasms of the nasal cavity and paranasal sinuses may arise from any of the tissues forming these structures, inclu...
Pharynx, Guttural Pouches, Larynx, and Trachea
Inflammation (Pharyngitis, Laryngitis, and Tracheitis). Inflammation of the pharynx, larynx, and trachea is important because of...
Parasitic Diseases of the Larynx and Trachea. Parasitic infections of the larynx and trachea can cause obstruction with dramatic...
Respiratory System: Transitional and Air Exchange Components
Alveolar Filling Disorders. Alveolar filling disorders are a heterogeneous group of lung diseases characterized by abnormal surf...
Inflation Disturbances of the Lung. To achieve gaseous exchange, a balanced ratio of the volumes of air to capillary blood must ...
Circulatory Disorders. Lungs are extremely well-vascularized organs with a dual circulation provided by pulmonary and bronchial ...
Neoplasms. Lung cancer in animals is rare, unlike in human beings, in which the incidence is alarming and continues to be the nu...
Thoracic Cavities, Mediastinum, and Pleura
Degenerative Disorders
Pleural Calcification. Pleural calcification is commonly found in dogs and less often in cats with chronic uremia. Lesions appea...
Pneumothorax. Pneumothorax is the presence of air in the thoracic cavity where there should normally be negative pressure to fac...
Circulatory and Lymphatic Disorders
Pleural Effusion. Pleural effusion is a general term used to describe accumulation of any fluid (transudate, modified transudate...
Inflammation of the Pleurae
Pleuritis or Pleurisy. Inflammation of the visceral or parietal pleurae is called pleuritis or pleurisy (mostly used in human me...
Neoplasms of the Pleura
Primary Neoplasm of the Pleura: Mesothelioma. Mesothelioma is a rare neoplasm of the thoracic, pericardial, and peritoneal mesot...
Secondary Neoplasms of the Pleura. Secondary tumors may also spread into the visceral and parietal pleura. Thymomas are rare neo...
Diseases of Horses
Respiratory System: Conducting Component
Hypoplastic Epiglottis, Epiglottic Entrapment, and Dorsal Displacement of the Soft Palate. Anomalies, such as hypoplastic epiglo...
Subepiglottic and Pharyngeal Cysts. Anomalous lesions, such as subepiglottic and pharyngeal cysts, are occasionally seen in hors...
Degenerative Disorders
Nasal Amyloidosis. Amyloidosis, the deposition of amyloid protein (fibrils with a β-pleated configuration) in various tissues, h...
Progressive Ethmoidal Hematoma. Progressive ethmoidal hematoma (PEH) is important in older horses and is characterized clinicall...
Laryngeal Hemiplegia. Laryngeal hemiplegia (paralysis), sometimes called roaring in horses, is a common but obscure disease char...
Circulatory Disorders
Exercise-Induced Pulmonary Hemorrhage. Exercise-induced pulmonary hemorrhage (EIPH) is a specific form of pulmonary hemorrhage i...
Inflammation
Equine Asthma Syndrome. Recently the term equine asthma syndrome (EAS) has been used as a collective term to include chronic inf...
Equine Pharyngeal Lymphoid Hyperplasia. Equine pharyngeal lymphoid hyperplasia, or pharyngitis with lymphoid follicular hyperpla...
Inflammation of Guttural Pouches. The guttural pouches of horses are large diverticula (300 to 500 mL) of the ventral portion of...
Infectious Diseases
Viral Infections. Viruses, such as equid alphaherpesviruses, influenza virus, adenovirus, and equine rhinitis viruses, cause mil...
Bacterial Infections. Strangles, glanders, and melioidosis of horses are all systemic bacterial diseases that cause purulent rhi...
Respiratory System: Transitional and Air Exchange Components
Viral Pneumonias. Viral infections of the respiratory system, particularly EVR and equine influenza, are important diseases of h...
Aspiration Pneumonia. Aspiration pneumonia is often a devastating sequela to improper gastric tubing of horses, particularly exo...
Thoracic Cavities, Mediastinum, and Pleurae
Pleuritis
Diseases of Ruminants (Cattle, Sheep, and Goats)
Diseases of Cattle
Respiratory System: Transitional and Air Exchange Components
Thoracic Cavities, Mediastinum, and Pleurae
Pleuritis. Pleuritis in cattle most often results from direct extension from pneumonia (pleuropneumonia) and is seen with infect...
Diseases of Sheep and Goats
Bacterial Infections. Infectious rhinitis is only sporadically reported in sheep and goats, and most of these cases are caused b...
Foreign Body Rhinitis. Foreign body rhinitis caused by plant material is sporadically seen cattle, sheep, and goats (Fig. 9.103)...
Respiratory System: Transitional and Air Exchange Components
Thoracic Cavities, Mediastinum, and Pleurae
Pleuritis. Similar to cattle, pleuritis in small ruminants most often results from parapneumonic spread and is seen as a compone...
Diseases of Pigs
Respiratory System: Conducting Component
Inclusion Body Rhinitis. Inclusion body rhinitis is a disease of young pigs with high morbidity and low mortality caused by a po...
Bacterial Infections
Progressive Atrophic Rhinitis. A common worldwide disease of pigs, atrophic rhinitis (progressive atrophic rhinitis) is characte...
Necrotic/Necrosuppurative Rhinitis (Bullnose). Necrotic rhinitis is a disorder of young pigs characterized by necrosis and suppu...
Respiratory System: Transitional and Air Exchange Components
Pneumonias of Pigs
Foreign Body Pneumonia. Foreign body pneumonia is a granulomatous pneumonia that occurs frequently in pigs after inhalation of v...
Thoracic Cavities, Mediastinum, and Pleurae
Pleuritis
Diseases of Dogs
Respiratory System: Conducting Component
Brachycephalic Airway Syndrome. Brachycephalic airway syndrome is a clinical term that refers to increased airflow resistance ca...
Tracheal Hypoplasia and Tracheal Collapse. Tracheal hypoplasia occurs most often in English bulldogs and Boston terriers; the tr...
Canine Laryngeal Paralysis. Atrophy of laryngeal muscles resulting from degeneration of the recurrent laryngeal nerves and the a...
Viral Infections
Canine Infectious Respiratory Disease. Canine infectious respiratory disease (CIRD), formerly called canine tracheobronchitis or...
Bacterial Infections
Mycotic and Algae Infections
Parasitic Infections
Linguatula serrata. Linguatula serrata is a rare but highly specialized pentastomid parasite that shares some morphologic featur...
Eucoleus boehmi. Eucoleus boehmi is a nematode parasite that occurs in the nasal passage and paranasal sinuses of wild and domes...
Oslerus osleri. Oslerus osleri is a nematode parasite of dogs and other Canidae that causes characteristic protruding nodules in...
Other Parasitic Infections. The nasal cavity and paranasal sinuses of dogs can occasionally be infested with other parasites, in...
Allergic Rhinitis
Other Causes of Rhinitis
Neoplasms
Transmissible Venereal Tumor. Transmissible venereal tumor (TVT) is a unique transplantable tumor commonly found in dogs, partic...
Respiratory System: Transitional and Air Exchange Components
Pneumonias of Dogs
Bacterial Pneumonias. Dogs generally develop bacterial pneumonias when the pulmonary defense mechanisms have been impaired. Past...
Mycotic Pneumonias. Mycotic pneumonias are serious diseases seen commonly in animals in some regions. There are two main types: ...
Aspiration Pneumonia. Aspiration pneumonia is an important form of pneumonia that occurs in dogs when vomit or regurgitated mate...
Other Pneumonias. Idiopathic pulmonary fibrosis is a rare condition of uncertain etiology reported in the West Highland white te...
Thoracic Cavities, Mediastinum, and Pleurae
Pyothorax
Diseases of Cats
Respiratory System: Conducting Component
Viral Infections
Feline Viral Rhinotracheitis. Feline viral rhinotracheitis (FVR) is a common, worldwide respiratory disease of cats caused by Fe...
Feline Calicivirus. Feline rhinitis can be caused by different strains of FCV. It is an important infection of the respiratory s...
Bacterial Infections
Feline Chlamydiosis. Feline chlamydiosis is a persistent respiratory infection of cats caused by Chlamydia felis and less often ...
Mycotic Infections
Cryptococcosis. The most common mycotic infection in the feline nasal cavity is caused by Cryptococcus neoformans (C. neoformans...
Other Causes of Rhinitis and Sinusitis
Neoplasms
Respiratory System: Transitional and Air Exchange Components
Pneumonias of Cats
Aspiration Pneumonia. Aspiration pneumonias are common in cats as a result of vomiting, regurgitation, dysphagia, or anesthetic ...
Thoracic Cavities, Mediastinum, and Pleurae
Pyothorax
Feline Infectious Peritonitis
Components of the Respiratory System
Conducting Component
Transitional Component
Air Exchange Component
Species Differences in Structure
Normal Microbiota (Flora) of the Respiratory System
Thoracic Cavities, Mediastinum, and Pleurae
10 - Cardiovascular System, Pericardial Cavity, and Lymphatic Vesselsa
Function
Myocardium
Cardiac Conduction System
E-Appendix 10.1 Necropsy Assessment of Heart and Vascular Structures
E-Appendix 10.2 Examination of the Cardiovascular and Lymphatic Systems at Necropsy and Tissue Sampling for Histopathologic Eval...
Endocardium and Heart Valves
Pericardium and Epicardium
Blood and Lymphatic Vascular Systems
Dysfunction/Responses to Injury
Heart Failure
Congestive Heart Failure
Pathophysiology of Heart Failure
Cardiac Syncope. Cardiac syncope, an acute expression of cardiac disease, is characterized clinically by collapse, loss of consc...
Indices of Cardiac Function
Systolic and Diastolic Heart Failure
Concentric Hypertrophy
Eccentric Hypertrophy
Neuroendocrine Compensatory Mechanisms in Heart Failure
Role of Catecholamines in the Progression of Heart Failure
Role of Baroreceptors in the Progression of Heart Failure
Role of Renin-Angiotensin-Aldosterone System in the Progression of Heart Failure
Role of Natriuretic Peptides and Nitric Oxide in the Progression of Heart Failure
Clinical Diagnostic Procedures
Myocardium
Disturbances of Circulation
Hemorrhage: Trauma (Physical Injury). Hemorrhage of the myocardium most commonly occurs from direct trauma to the chest. The phy...
Disturbances of Growth
Myocardial Hypertrophy. See the discussion on hypertrophy in Chapter 1, Mechanisms and Morphology of Cellular Injury, Adaptation...
Physiologic Atrophy. Physiologic atrophy of heart muscle may occur in confined animals and also occurs as a result of decompensa...
E-Appendix 10.3 Clinical Diagnostic Procedures
Neoplastic Transformation. See Chapter 6, Neoplasia and Tumor Biology, for a discussion of the mechanisms involved in neoplastic...
Cell Degeneration and Death
Oncotic Necrosis. Cardiac muscle cells (myocytes), like other cells in the body, can be affected by a variety of injurious stimu...
Apoptosis. Apoptosis (programmed cell death of cardiomyocytes [see Chapter 1, Mechanisms and Morphology of Cellular Injury, Adap...
Fatty Infiltration. Fatty infiltration is the presence of increased numbers of lipocytes interposed between myocardial fibers. T...
Fatty Degeneration. Fatty degeneration (fatty change) is the accumulation of abundant lipid droplets in the sarcoplasm of myocyt...
Hydropic Degeneration. Hydropic degeneration, a distinctive microscopic alteration in cardiac muscle cells, is associated with c...
Myofibrillar Degeneration. Myofibrillar degeneration (myocytolysis) represents a distinctive sublethal injury of cardiac muscle ...
Lipofuscinosis. Lipofuscinosis (brown atrophy) of the myocardium occurs in aged animals and in animals with severe cachexia, but...
Mineralization. Myocardial mineralization (calcium) is a prominent feature in several diseases, such as hereditary calcinosis in...
Myocardial Necrosis. Myocardial necrosis can result from a number of causes, including nutritional deficiencies, chemical and pl...
Inflammation
Myocarditis. The various infectious diseases that cause myocarditis in animals are summarized in Box 10.4. Myocarditis generally...
Cardiac Conduction System
Endocardium and Heart Valves
Hemorrhage. Endocardial hemorrhages are commonly seen and may be the result of trauma or septicemias, especially those with endo...
Disturbances of Growth
Valvular Anomalies and Dysplasia. See the discussion on valvular anomalies and dysplasia in the section on Diseases Affecting Mu...
Cellular Degeneration and Death
Myxomatous Valvular Degeneration (Endocardiosis). See the section on Myxomatous Valvular Degeneration (Valvular Endocardiosis), ...
Mineralization. Mineralization of the endocardium is seen with vitamin D toxicity, calcinogenic plant toxicosis in cattle, and c...
Inflammation
Pericardium and Epicardium
Blood and Lymphatic Vascular Systems
Disturbances of Circulation
Hemorrhage. Hemorrhage resulting from vascular injury is a frequent lesion of the epicardium, endocardium, and myocardium. Hemor...
Effusions. See section on Diseases Affecting Multiple Species of Domestic Animals, Disorders of the Pericardium and Epicardium
Disturbances of Growth
Hypertrophy. Arterial hypertrophy is a response to sustained increases in pressure or volume loads. Affected vessels are general...
Inflammation
Arteritis and Vasculitis. Arteritis occurs as a feature of many infectious and immune-mediated diseases (Box 10.5). Often all ty...
Lymphangitis. The endothelial cells lining the lymphatic vessels are subject to the same reactions to injury and inflammation as...
Aging of the Cardiovascular System
Portals of Entry/Pathways of Spread
Myocardium
Endocardium and Heart Valves
Epicardium and Pericardium
Blood and Lymphatic Vascular Systems
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Disorders of the Myocardium
Hemorrhage: Trauma (Physical Injury)
Cardiomyopathies
Hypertrophic Cardiomyopathy. Hypertrophic cardiomyopathy (HCM) is the most common feline primary myocardial disease, and it occu...
Restrictive Cardiomyopathy. Restrictive cardiomyopathy (RCM) occurs infrequently. RCM is a functional term rather than disease e...
Arrhythmogenic Right Ventricular Cardiomyopathy. Arrhyth­­mo­genic right ventricular cardiomyopathy (ARVC) is an important cardi...
Unclassified Cardiomyopathy. This is a nebulous category that includes cases with left or bilateral atrial dilation, normal to n...
Molecular Mechanisms of Hereditary Cardiomyopathies. Our understanding of the molecular mechanisms of the hereditary cardiomyopa...
Neoplasms
Myocardial Necrosis and Mineralization
Ionophore-Induced Myocardial Degeneration. Ionophores (polyether antibiotics), such as monensin, lasalocid, salinomycin, and nar...
Gossypol-Induced Myocardial Degeneration. Gossypol-indu­ced myocardial degeneration can follow the ingestion of cottonseed or co...
Chemotherapeutic Agent-Induced Myocardial Degeneration. Cardiotoxicity has emerged as a significant clinical entity in veterinar...
Sarcocystis: Parasitic Infection
Disorders of the Cardiac Conduction System
Cell Degeneration and Death
Schwannomas
Disorders of the Endocardium and Heart Valves
Endocardial Fibroelastosis
Valvular Hematomas
Valvular Lymphocysts
Ulcerative Endocarditis (Uremic Endocarditis)
Myxomatous Valvular Degeneration (Valvular Endocardiosis)
Endocardial Mineralization
Endocardial Fibrosis
Vegetative Valvular and Mural Endocarditis
Atrial Thrombosis
Disorders of the Pericardium and Epicardium
Peritoneopericardial Diaphragmatic Hernias. PPDHs occur in cats and dogs with incomplete development of the diaphragm. PPDHs are...
Partial/Complete Absence (Agenesis) of the Pericardial Sac. Partial or complete absence of the pericardial sac is an incidental ...
Intrapericardial Cysts. Benign intrapericardial cysts are rare, large, fluid-filled masses within the pericardial space that ori...
Hemorrhage
Effusions
Pericardial Dilation. The pericardium responds to excess fluid in the pericardial space by dilation. However, this outcome requi...
Hydropericardium. Hydropericardium occurs in those diseases that have generalized edema (see Fig. 10.50). Thus, ascites and hydr...
Hemopericardium. Hemopericardium is an accumulation of whole blood in the pericardial sac (Figs. 10.51 and 10.52). Death often o...
Serous Atrophy
Epicardial Calcification
Gout
Pericarditis
Fibrinous Pericarditis. Hematogenous spread of specific organisms may result in fibrinous pericarditis. Mannheimiosis, blackleg,...
Disorders of the Blood and Lymphatic Vascular Systems
Disorders of Blood Vessels
Hemothorax and Hemoabdomen. Hemothorax and hemoabdomen arise from spontaneous or traumatic rupture of large arteries or veins or...
Aortic Rupture and Rupture of Large Arteries. Aortic rupture and rupture of large arteries can be the sequelae of severe trauma ...
High-Altitude Disease (High-Mountain Disease/Brisket Disease). High-altitude disease occurs predominately in cattle but also in ...
Hemangiosarcoma. Cardiac HSA is an important neoplasm of dogs and can arise either in the heart (primary) or by metastasis (seco...
Cell Degeneration and Death. Toxicants that affect vessels are listed in E-Box 10.3. Generalized vascular degenerative diseases ...
Hyaline Degeneration, Fibrinoid Necrosis, and Amyloidosis. Hyaline degeneration, fibrinoid necrosis, and amyloidosis are vascula...
Omphalophlebitis (“Navel Ill”). Omphalophlebitis (“navel ill”) is inflammation of the umbilical vein that often occurs in neonat...
Jugular Thrombophlebitis. Jugular thrombophlebitis (see Fig. 10.26) may be associated with indwelling jugular catheters, and the...
Disorders of Lymphatic Vessels
Rupture of the Thoracic Duct. Rupture of the thoracic duct, either as a result of trauma or from spontaneous disruption, causes ...
Lymphedema. Lymphedema specifically refers to accumulation of fluid in interstitial space secondary to abnormal lymphatic absorp...
Lymphangioma. Lymphangioma is a rare benign neoplasm composed of lymphatic channels. Lymphangiosarcoma, the malignant counterpar...
Lymphangitis. Lymphangitis is a feature of many diseases (see Box 10.6). The affected vessels are often located in the distal li...
Diseases of Horses
White Snakeroot–Induced Myocardial Degeneration
Ionophore-Induced Myocardial Degeneration
Fibrinous Pericarditis
Equine Viral Arteritis
African Horse Sickness: Subacute Cardiac Form
Cranial Mesenteric Arteritis and Thrombosis
Aortoiliac Thrombosis
Arterial Intimal Calcification
Glanders Disease (Farcy): Cutaneous Form
Miscellaneous Cutaneous Lymphangitides
Chronic Progressive Lymphedema in Draft Horses
Diseases of Ruminants (Cattle, Sheep, and Goats)
Blackleg Myocarditis
East Coast Fever (Theileria parva)
Foot-and-Mouth Disease
Malignant Catarrhal Fever
High-Altitude Disease (Bovine High-Mountain Disease/Brisket Disease)
Eosinophilic Myocarditis
Valvular Hematomas
Valvular Lymphocysts
Vegetative Valvular Endocarditis
Endocardial Mineralization
Fibrinous Pericarditis
Suppurative Pericarditis (Traumatic Reticulopericarditis)
Thrombotic Meningoencephalitis
Thrombosis of the Caudal Vena Cava
Foreign Parasitic Diseases
Johne’s Disease
Anthrax
Diseases of Pigs
Encephalomyocarditis
Endocarditis
Fibrinous Pericarditis
Porcine Polyserositis (Glasser’s Disease, Streptococcus suis II)
Dietary Microangiopathy: Mulberry Heart Disease
Fibrinoid Necrosis of Blood Vessels
Edema Disease (Cerebrospinal Angiopathy)
Erysipelosis (Erysipelothrix rhusiopathiae)
Porcine Polyserositis (Streptococcus suis II)
African Swine Fever (Warthog Disease, African Pig Disease)
Hog Cholera/Classical Swine Fever (Swine Fever, Swine Plague, Schweinpest)
Diseases of Dogs
Dilatative (Congestive) Cardiomyopathy
Hypertrophic Cardiomyopathy
Patent Ductus Arteriosus
Cardiac Neoplasms
Canine Parvovirus Myocarditis
Trypanosoma cruzi
Neurogenic Cardiomyopathy (Heart-Brain Syndrome)
Myxomatous Valvular Degeneration (Valvular Endocardiosis)
Endocarditis
Idiopathic Pericardial Effusion (Hemorrhagic Pericardial Effusion)
Hemangiosarcoma and Hemangioma
Heart-Base Tumors
Medial Necrosis and Hemorrhage
Segmental Arterial Mediolysis
Fibrocartilaginous Embolism
Pulmonary Artery Thromboembolism
Arterial Thromboembolism and Thrombosis
Thrombosis of the Femoral Artery
Heartworm Dirofilariasis (Dirofilaria immitis)
Polyarteritis: “Beagle Pain Syndrome”
Primary Lymphedema
Primary Intestinal Lymphangiectasia
Diseases of Cats
Hypertrophic Cardiomyopathy
Endomyocarditis
Hemopericardium
Hydropericardium
Pericarditis
Arterial Thromboembolism
Feline Infectious Peritonitis
Heartworm-Associated Respiratory Disease
Foreign Parasitic Diseases
Development of the Heart and Great Vessels
Macroscopic Structure
Myocardium
Cardiac Conduction System
Endocardium and Heart Valves
Pericardium and Epicardium
Blood and Lymphatic Vascular Systems
Blood Vessels. The aorta originates from the LV and provides oxygenated blood to the entire body via arteries. In a treelike man...
Lymphatic Vessels. Lymphatic vessels are thin-walled, endothelial-lined channels that originate near the capillary beds and serv...
Microscopic Structure
Myocardium
Cardiac Conduction System
Sinoatrial Node. The SAN is positioned adjacent to the epicardial adipose tissue and is often centered around a branch of the ri...
Atrioventricular Node, Atrioventricular Bundle, and Bundle Branches. The AVN lies within the right atrial subendocardium and con...
Autonomic Nervous System. The nerve supply to the heart is autonomic and includes sympathetic, parasympathetic, and nonadrenergi...
Endocardium and Heart Valves
Pericardium and Epicardium
Blood and Lymphatic Vascular Systems
Necropsy Assessment of Heart and Vascular Structures
Examination of the Cardiovascular System and Lymphatic Vessels at Necropsy and Tissue Sampling for Histopathologic Evaluation
11 - The Urinary Systema
E-Appendix 11.1: Postmortem Examination and Evaluation of the Kidney
Bowman’s Capsule. Bowman’s capsule is a cup-shaped, membranous sac that encloses each glomerulus and is separated from the glome...
Tubules
Interstitium
Vasculature
Function
Initial Formation of Urine at the Glomerular Filtration Barrier
Juxtaglomerular Apparatus and the Renin-Angiotensin-Aldosterone System
Modification of Primary Urine within the Proximal and Distal Convoluted Tubules and Collecting Ducts
Dysfunction/Responses to Injury
Dysfunction and Renal Failure
Acute Renal Failure. Functionally, acute renal failure can be caused by prerenal (compromised renal perfusion), intrarenal (comp...
Chronic Renal Failure. Chronic renal failure usually results from progressive renal disease with loss of nephrons and severe fib...
Responses to Injury
Renal Corpuscle (Glomerulus and Bowman’s Capsule). The functions of the glomerulus are numerous and glomerular health is crucial...
Tubules. Renal tubular epithelial cells can respond to injury by undergoing degeneration, necrosis, apoptosis, and/or atrophy. T...
Interstitium
Aging of the Kidney
Portals of Entry/Pathways of Spread
Kidney as a Whole
Renal Corpuscle (Glomerulus and Bowman’s Capsule)
Hematogenous. The renal cortex has a high rate of blood flow; therefore, the sustaining blood supply can provide a portal of hem...
Tubules
Ascending Injury. Ascension from the exterior via the urethra into the urinary bladder and subsequently from the urinary bladder...
Hematogenous. The luminal and abluminal surfaces of epithelial cells lining renal tubules can be exposed to systemic blood-borne...
Glomerular Filtrate. Substances secreted into the glomerular filtrate can produce localized trauma to tubular lining cells such ...
Interstitium
Ascending Injury. See previous section on Tubules
Vasculature (Interstitial Capillaries and Vasa Recta)
Defense Mechanisms/Barrier Systems
Renal Corpuscle (Glomerulus and Bowman’s Capsule)
Glomerular Filtration Barrier. The most important of these barrier systems is the glomerular filtration barrier (see Fig. 11.7)....
Glomerular Mesangium. The glomerulus is equipped with specialized mesangial cells, pluripotent mesenchymal cells (see Fig. 11.6)...
Tubules
Interstitium
Vasculature
Developmental Anomalies
Renal Aplasia, Agenesis, Hypoplasia, and Dysplasia. Renal aplasia and agenesis both refer to failure of the development of one o...
Ectopic and Fused Kidneys. Ectopic kidneys are misplaced from their normal location because of abnormal migration during fetal d...
Renal Cysts. Renal cysts are spherical, thin-walled, clear fluid–filled, variably sized distensions most commonly of renal tubul...
Disorders of the Renal Corpuscle (Glomerulus and Bowman’s Capsule)
Immune-Complex Mediated Glomerulonephritis. Glomerulonephritis (GN) most often results from immune-mediated mechanisms, most not...
Membranous Glomerulonephritis. Membranous GN is characterized by diffuse glomerular capillary basement membrane thickening witho...
Membranoproliferative Glomerulonephritis. Membranoproliferative GN (mesangioproliferative, mesangiocapillary) is characterized b...
Glomerulosclerosis. In chronic GN, severely affected glomeruli shrink and become hyalinized because of an increase in both fibro...
Glomerular Amyloidosis. Amyloid, an insoluble fibrillar protein with a β-pleated sheet conformation, is produced after incomplet...
Acute Suppurative Glomerulonephritis: Embolic Glomerulonephritis. Glomerulitis refers to inflammation limited to the glomerulus....
Viral Glomerulonephritis. Glomerulitis, caused by a direct viral insult to the glomerulus, occurs in acute systemic viral diseas...
Chemical Glomerulonephritis. Although much less common than the immune-mediated forms of GN, chemically induced glomerular disea...
Disorders of the Tubules
Inherited Abnormalities of Renal Tubular Function. Inherited abnormalities in tubular metabolism, in transport, or in reabsorpti...
Toxic Acute Tubular Injury. Acute tubular injury as described in the section on tubular response to injury, occurs after exposur...
Disorders of the Renal Pelvis
Hydronephrosis. Hydronephrosis occurs in all domestic animals and refers to dilation of the renal pelvis and accompanying renal ...
Pyelonephritis. Inflammation of the renal pelvis (pyelitis) with extension into the renal parenchyma causing concomitant tubuloi...
Papillary (Medullary Crest) Necrosis. Necrosis of the renal papillae (cow and pig), or their counterpart, the medullary crest (o...
Disorders of the Interstitium
Granulomatous Nephritis. Granulomatous nephritis is an interstitial disease that often accompanies chronic systemic diseases tha...
Xanthogranulomas. Cats with inherited hyperlipoproteinemia have xanthogranulomas in various organs, including the kidneys. Simil...
Renal Interstitial Amyloidosis. Although glomeruli are the most common renal sites for deposition of amyloid in most domestic an...
Neoplasia
Mesenchymal Tumors. Fibromas, fibrosarcomas, hemangiomas, hemangiosarcomas, renal interstitial cell tumors, and undifferentiated...
Tumors of Embryonal Origin. Nephroblastomas (or Wilms tumor) are the most common renal neoplasms of pigs and chickens and are us...
Metastatic Tumors. Carcinomas and sarcomas arising in other organs metastasize to the kidneys and are characteristically compose...
Diseases of Horses
Embolic Glomerulonephritis (Actinobacillus equuli)
Myoglobinuric Acute Tubular Injury
Patent Urachus
Klossiella equi Infection
Diseases of Ruminants (Cattle, Sheep, and Goats)
Oak-Induced Acute Tubular Injury (Quercus Spp.)
Pulpy Kidney Disease
Multifocal Lymphoplasmacytic Interstitial Nephritis (White-Spotted Kidney)
Malignant Catarrhal Fever
Renal Leptospirosis
Bacillary Hemoglobinuria (Red Water Disease)
Hairy Vetch Toxicosis (Vicia Spp.)
Pyelonephritis
Renal Lymphoma
Amyloidosis
Diseases of Pigs
Glomerulonephritis
Toxic Nephritis
Renal Leptospirosis
Kidney Worm (Stephanurus dentatus)
Erysipelas (Erysipelothrix rhusiopathiae)
Diseases of Dogs
Focal Segmental Glomerulosclerosis
Cutaneous and Renal Glomerular Vasculopathy (Alabama Rot)
Renal Leptospirosis
Canine Lyme Nephritis
Infectious Canine Hepatitis
Canine Herpesvirus
Pyelonephritis
Progressive Juvenile Nephropathies
Abnormalities of Renal Tubular Function
Toxic Acute Tubular Injury
Grape Toxicity. Ingestion of grapes or raisins (Vitis vinifera fruit) can lead to a syndrome of acute renal failure and uremia a...
Aminoglycoside-induced Acute Tubular Injury. Aminoglycoside antimicrobials, such as gentamicin, neomycin, kanamycin, tobramycin,...
Parasites
Renal Carcinoma
Diseases of Cats
Granulomatous Nephritis: Feline Infectious Peritonitis
Renal Lymphoma
Toxic Acute Tubular Injury
Lily Toxicity. Cats are prone to a species-specific toxicity associated with ingestion of any portion of lily plants (Lilium spp...
Structure
Ureters
Urinary Bladder
Urethra
Function
Ureters
Urinary Bladder and Urethra
Dysfunction/Responses to Injury
Ureter, Urinary Bladder, and Urethra
Aging of the Lower Urinary Tract
E-Appendix 11.2: Postmortem Examination and Evaluation of the Lower Urinary Tract
Portals of Entry/Pathways of Spread
Ascending Infection
Descending Infection
Direct Extension or Exposure from the Lumen
Direct Penetration from the Abdomen
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Developmental Anomalies
Aplasia, Agenesis, Hypoplasia, and Dysplasia. Ureteral aplasia (agenesis) is the lack of formation of a recognizable ureter, and...
Ectopic Ureters. Ectopic ureters are ureters that empty into the urethra, vagina, neck of the urinary bladder, ductus deferens, ...
Patent Urachus. The most common malformation of the urinary bladder is persistent or patent urachus (pervious urachus), and it i...
Hydroureter
Urolithiasis (Obstructive Disease)
Inflammatory Disorders
Acute Cystitis. Inflammation of the urinary bladder (cystitis) is common in domestic animals and may be acute or chronic. Becaus...
Chronic Cystitis. Chronic cystitis occurs in several different forms based on the pattern and type of inflammatory response. The...
Toxic Cystitis. In veterinary species, toxic cystitis is uncommon, but it is well established in three domestic animal species. ...
Mycotic Cystitis. Mycotic cystitis occurs occasionally in domestic animals when opportunistic fungi, such as Candida albicans or...
Neoplasia
Epithelial Tumors. Approximately 80% of the neoplasms of the lower urinary tract are epithelial in origin and are classified as ...
Mesenchymal Tumors. Mesenchymal tumors, including leiomyomas, leiomyosarcomas, fibromas, fibrosarcomas, rhabdomyosarcomas, lymph...
Diseases of Horses
Cantharidin-Induced Hemorrhagic Cystitis
Diseases of Ruminants (Cattle, Sheep, and Goats)
Urolithiasis (Obstructive Disease)
Bracken Fern-Induced Hemorrhagic Cystitis (Enzootic Hematuria)
Bracken Fern–Induced Neoplasia. Bracken fern is one of the best-established toxic causes of neoplasia in veterinary species. Uri...
Diseases of Pigs
Urolithiasis (Obstructive Disease)
Diseases of Dogs
Cyclophosphamide-Induced Sterile Hemorrhagic Cystitis
Chronic Cystitis
Urolithiasis (Obstructive Disease)
Struvite Calculi
Calcium Oxalate Calculi
Uric Acid and Ammonium Biurate Calculi
Xanthine Calculi
Cystine Calculi
Urothelial Cell Carcinomas
Diseases of Cats
Feline Idiopathic Cystitis
Urolithiasis (Obstructive Disease)
Struvite Calculi
Calcium Oxalate Calculi
Renal Corpuscle (Glomerulus and Bowman’s Capsule)
Glomerulus. Macroscopically, glomeruli are difficult to detect in the normal kidney but can be accentuated on cut section by les...
12 - Endocrine Systema
Dysfunction/Responses to Injury
Mechanisms of Endocrine Diseases
Hypofunction of an Endocrine Gland
Primary Hypofunction. Hypofunction is considered primary if the hormonal deficiency is the result of a biochemical defect in syn...
Secondary Hypofunction. Hypofunction is considered secondary if the cause arises outside the hypofunctioning gland. Often, this ...
Hyperfunction of an Endocrine Gland
Primary Hyperfunction. In primary hyperfunction, the cells of the affected endocrine gland autonomously (i.e., without dependenc...
Secondary Hyperfunction. In secondary hyperfunction, excessive hormone production is a response to a signal (e.g., a trophic hor...
Hypersecretion of Hormones or Hormone-Like Factors by Nonendocrine Neoplasms
Endocrine Dysfunction Caused by Failure of Target Cell Response
Iatrogenic Syndromes of Hormone Excess
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Disorders of the Adenohypophysis
Proliferative Disorders of the Adenohypophysis
Pituitary Carcinomas. Pituitary carcinomas are exceedingly rare, but that is at least partly because of stringent classification...
Adenomas of the Pars Distalis. Adenomas can arise from any of the trophic hormone-producing cells of the pars distalis. Dependin...
E-Table 12.1
Adenomas of the Pars Intermedia. Adenomas in the pars intermedia are usually derived from melanotrophs. Equine pituitary adenoma...
Miscellaneous Disorders of the Adenohypophysis
Cellular Atrophy, Degeneration, and Death. Physiologic hypophyseal atrophy is the result of negative feedback from targeted endo...
Inflammation. The pituitary gland can become inflamed as part of a systemic infection, but there are few, if any, infectious age...
Disorders of the Neurohypophysis
Diabetes Insipidus
Neoplasms
Other Neoplastic Disorders of the Hypophysis
Secondary Neoplasms
Suprasellar Neoplasms
Disorders of the Thyroid Gland
Developmental Malformations
Ectopic Thyroid Tissue. Ectopic thyroid tissue is usually encountered from the base of the tongue along the path of descent of t...
Accessory Thyroid Tissue and Thyroglossal Duct Cysts. Accessory thyroid tissue is derived from remnants of the thyroglossal duct...
Follicular Hyperplasia and Goiter
Iodine Deficiency. Iodine deficiency, especially during the fetal and neonatal period when the need for thyroid hormones is grea...
Goitrogens. Goitrogens are compounds, including plants, drugs, and other chemicals, that cause hyperplastic goiter. Marginal iod...
Thyroid Dyshormonogenesis. Mutations of any of the genes involved in thyroid hormone synthesis can result in dyshormonogenesis (...
Multinodular Goiter. Multifocal follicular hyperplasia in geriatric horses or dogs is typically an incidental finding without no...
Follicular Atrophy
Colloid Goiter. Colloid goiter is the involutional stage of hyperplastic goiter after repletion of dietary iodine in the case of...
Lymphocytic (Immune-Mediated) Thyroiditis. Autoimmune thyroid disease, with infiltration of the gland by thyroid-reactive lympho...
Follicular Neoplasms
Follicular Adenomas. Thyroid follicular adenomas are more commonly diagnosed in cats than in dogs. In dogs, most thyroid follicu...
Follicular Carcinomas. Thyroid follicular carcinomas are diagnosed mainly in dogs. Follicular carcinomas (Fig. 12.28; E-Fig. 12....
Thyroid Medullary (C-Cell) Proliferative Lesions
Thyroid C-Cell Hyperplasia. Bulls, especially those fed a high-calcium diet designed for dairy cows, are likely to develop C-cel...
Thyroid C-Cell Neoplasms. Thyroid C-cell neoplasms are diagnosed mainly in older horses and dairy bulls, in which they can be as...
Disorders of the Parathyroid Glands
Parathyroid (Kürsteiner’s) Cysts. Cysts (Fig. 12.31; E-Fig. 12.20) in or immediately adjacent to a parathyroid gland, presumably...
Chief Cell Atrophy and Hypoparathyroidism
Chief Cell Proliferation and Hyperparathyroidism
Primary Hyperparathyroidism. Primary hyperparathyroidism is the result of autonomous hypersecretion of PTH by hyperplastic or ne...
Secondary Hyperparathyroidism. Secondary chief cell hyperplasia is typically diffuse, affecting all parathyroid glands (Fig. 12....
Pseudohyperparathyroidism: Humoral Hypercalcemia of Malignancy
Disorders of the Adrenal Gland
Developmental Disorders of the Adrenal Cortex. Maturation of the fetal adrenal gland and the onset of parturition depend on an i...
Adrenocortical Atrophy, Degeneration, or Cell Death. Atrophy of the zonae fasciculata and reticularis is often secondary to insu...
Disorders of the Adrenal Medulla
Disorders of Pancreatic Islet Cells
Diabetes Mellitus. Diabetes mellitus, diagnosed mainly in dogs and cats, is the result of a relative or absolute deficiency of i...
Hyperfunction of Pancreatic Islet Cells
β-Cell (Insulin-Secreting) Neoplasms (Insulinomas). Islet cell neoplasms (adenomas or carcinomas) are often functional. Most are...
Non-β Islet Cell Neoplasms. Non-β islet cell neoplasms are rare and include glucagonomas, gastrinomas, and somatostatinomas. Imm...
Disorders of the Pineal Gland
Inflammation
Neoplasms
Disorders of the Chemoreceptor Organs
Neoplasms
Neoplasms of the Carotid Body. Carotid body chemodectomas are usually unilateral and slow-growing. Benign tumors vary from 1 to ...
Neoplasms of the Aortic Body. Aortic body chemodectomas appear as a solitary mass or multiple nodules near the base of the heart...
Heart-Base Neoplasms Derived from Ectopic Thyroid Gland Tissue. Adenomas and carcinomas derived from ectopic thyroid tissue acco...
Obesity
Diseases of Horses
Dysfunction of the Pars Intermedia of the Pituitary Gland
Equine Metabolic Syndrome
Congenital Hypothyroidism-Dysmaturity Syndrome
Diseases of Ruminants (Cattle, Sheep, and Goats)
Adenohypophyseal Aplasia and Prolonged Gestation
Parturient Hypocalcemia
Diseases of Pigs
Metabolic Syndrome in Ossabaw Pigs
Diseases of Dogs
Pituitary Cysts and Pituitary Dwarfism
Hypothyroidism
Idiopathic Follicular Atrophy
Lymphocytic Thyroiditis
Apocrine Carcinoma of the Anal Sac Glands
Hyperadrenocorticism (Cushing’s Syndrome or Disease)
Primary Hypoadrenocorticism
Diabetes Mellitus
Diseases of Cats
Hyperthyroidism
Diabetes Mellitus
Hypothyroidism
Hyperadrenocorticism (Hypercortisolism)
Congenital Adrenal Hyperplasia
Hypersomatotropism
Pituitary Gonadotroph Adenoma
Hyperaldosteronism
Pituitary Gland (Hypophysis)
Adenohypophysis
Neurohypophysis
Thyroid Gland
Postmortem Examination of the Endocrine System
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid Glands
Adrenal Glands
Pancreatic Islets
Thyroid Follicular Cells
Thyroid C Cells
Parathyroid Glands
Adrenal Gland
Adrenal Cortex
Adrenal Medulla
Pancreatic Islets
Pineal Gland
Chemoreceptor Organs
Endocrine Activity in Adipose Tissue
13 - Bone Marrow, Blood Cells, and the Lymphoid/Lymphatic Systema
E-Appendix 13.1 Tests to Evaluate Platelet Function or Immune-Mediated Thrombocytopenia
Tests for Evaluating the Coagulation System
Extracellular Matrix. Hematopoiesis occurs in the interstitium between the venous sinusoids in the so-called hematopoietic space...
Monocyte-Macrophage System. Other components of the marrow include low numbers of resident macrophages, lymphocytes, and plasma ...
Hematopoietic Compartment
Hematopoiesis. Immature hematopoietic cells can be divided into three stages: stem cells, progenitor cells, and precursor cells....
Erythropoiesis. Erythropoiesis—from erythros (Gr., red)—refers to the production of red blood cells (RBCs), or erythrocytes, who...
Granulopoiesis and Monocytopoiesis (Myelopoiesis). Granulopoiesis is the production of neutrophils, eosinophils, and basophils, ...
Lymphopoiesis. Lymphopoiesis—from lympha (Latin, water)—refers to the production of new lymphocytes, including B lymphocytes, T ...
Thrombopoiesis. Thrombopoiesis—from thrombos (Gr., clot)—refers to the production of platelets, which are small (2 to 4 μm), rou...
Methods for Examination of the Bone Marrow
Gross and Microscopic Examination
Complete Blood Count
Additional Tests
Hemostasis Testing
Dysfunction/Responses to Injury
Bone Marrow
Blood Cells
Abnormal Concentrations of Blood Cells. The concentration of blood cells may be decreased, termed cytopenia (from kytos [Gr., ho...
Thrombocytosis. Thrombocytosis, or an increased concentration of platelets in the blood, is a relatively common, nonspecific fin...
Secondary Abnormal Structure or Function of Blood Cells. The preceding section focused on abnormalities in the number of blood c...
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Aplastic Anemia (Aplastic Pancytopenia)
Erythropoietic Porphyrias. Porphyrias are a group of hereditary disorders in which porphyrins accumulate in the body because of ...
Pyruvate Kinase Deficiency. Pyruvate kinase (PK) deficiency is an inherited autosomal recessive condition resulting from a defec...
Cytochrome-b5 Reductase Deficiency. Deficiency of cytochrome-b5 reductase (Cb5R, also known as methemoglobin reductase), the enz...
Glucose-6-Phosphate Dehydrogenase Deficiency. Deficiency of glucose-6-phosphate dehydrogenase (G6PD), the rate-controlling enzym...
Leukocyte Adhesion Deficiency. Leukocyte adhesion deficiency (LAD) is a fatal autosomal recessive defect of leukocyte integrins,...
Pelger-Huët Anomaly. Pelger-Huët anomaly (PHA) is a condition of hyposegmented granulocytes resulting from a lamin B receptor mu...
Chédiak-Higashi Syndrome
Glanzmann Thrombasthenia
CalDAG-GEFI Thrombopathia
von Willebrand Disease
Hereditary Coagulation Factor Deficiencies
Hereditary γ-Glutamyl Carboxylase Defect
Toxicoses
Oxidative Agents. A variety of oxidative toxins cause hemolytic anemia and/or MetHgb in domestic species. More common or well-ch...
Snake Envenomation. Hemolytic anemia from snake envenomation has been reported in horses, dogs, and cats. It is most commonly re...
Avitaminosis K
Nutritional and Metabolic Disorders
Iron Deficiency Anemia. Iron deficiency is usually not a primary nutritional deficiency but rather occurs secondary to depletion...
Hypophosphatemic Hemolytic Anemia. Marked hypophosphatemia is recognized as a cause of intravascular hemolytic anemia in postpar...
Infectious Diseases
Babesiosis (Piroplasmosis). Babesia spp. and Theileria spp., presented in the next section, are members of the order Piroplasmid...
Theileriosis (Piroplasmosis). Theileria spp. are tick-borne protozoal organisms that infect many domestic and wild animals world...
African Trypanosomiasis. Trypanosomes are flagellated protozoa that can infect all domesticated animals. The most important spec...
American Trypanosomiasis (Chagas’s Disease). Trypanosoma cruzi is the flagellated protozoal agent of American trypanosomiasis. I...
Anaplasmosis, Ehrlichiosis, Heartwater, and Tick-Borne Fever. Anaplasmosis, ehrlichiosis, heartwater, and tick-borne fever are t...
Clostridial Diseases. Certain Clostridium spp. may cause potentially fatal hemolytic anemias in animals; nonhemolytic lesions ar...
Leptospirosis. Leptospirosis is recognized as a cause of hemolytic anemia in calves, lambs, and pigs. Specific leptospiral organ...
Hemotropic Mycoplasmosis (Hemoplasmosis). The term hemotropic mycoplasmas, or hemoplasmas, encompasses a group of bacteria, form...
Immune-Mediated Disorders
Immune-Mediated Hemolytic Anemia. IMHA is a condition characterized by increased destruction of erythrocytes because of binding ...
Neonatal Isoerythrolysis. NI is a form of IMHA in which colostrum-derived maternal antibodies react against the newborn’s erythr...
Pure Red Cell Aplasia. PRCA is a rare bone marrow disorder characterized by absence of erythropoiesis and severe nonregenerative...
Immune-Mediated Neutropenia. Immune-mediated neutropenia is a rare condition that has been reported in horses, dogs, and cats. T...
Immune-Mediated Thrombocytopenia. IMTP is a condition characterized by immune-mediated destruction of platelets. It is a fairly ...
Neonatal Alloimmune Thrombocytopenia. A form of IMTP, known as neonatal alloimmune thrombocytopenia, is recognized in neonatal p...
Inflammatory Disorders
Hemophagocytic Syndrome. Hemophagocytic syndrome is a term used to describe the proliferation of nonneoplastic (i.e., polyclonal...
Disseminated Intravascular Coagulation. DIC is a syndrome characterized by continuous activation of both coagulation and fibrino...
Hematopoietic Neoplasia
Diagnostic Techniques Used to Classify Hematopoietic Neoplasms. Before the discussion of specific diseases, it is worthwhile to ...
Types of Hematopoietic Neoplasia
Plasma Cell Neoplasia. Plasma cell neoplasms are most easily categorized as myeloma or multiple myeloma, which arises in the bon...
Diseases of Horses
Flavin Adenine Dinucleotide Deficiency
Equine Infectious Anemia Virus
Diseases of Ruminants (Cattle, Sheep, and Goats)
Congenital Dyserythropoiesis in Polled Herefords
Erythrocyte Band 3 Deficiency in Japanese Black Cattle
Bovine Leukemia Virus
Bovine Viral Diarrhea Virus
Bovine Neonatal Pancytopenia
Diseases of Pigs
Diseases of Dogs
Cyclic Hematopoiesis
Phosphofructokinase Deficiency
Erythrocyte Structural Abnormalities
Scott’s Syndrome
Macrothrombocytopenia
Canine Distemper
Diseases of Cats
Increased Erythrocyte Osmotic Fragility
Cytauxzoonosis
Feline Leukemia Virus
Feline Immunodeficiency Virus
Lymphoid/Lymphatic System
Lymph Nodes
Stroma (Capsule, Trabeculae, and Reticulum). The lymph node is enclosed by a fibrous capsule penetrated by multiple afferent lym...
Cortex (Superficial or Outer Cortex [Lymphoid Follicles, B Lymphocytes]). The outer/superficial cortex contains the lymphoid fol...
Paracortex (Deep or Inner Cortex [T lymphocytes]). The diffuse lymphoid tissue of the paracortex (also referred to as the deep o...
Medulla (Medullary Sinuses and Cords). The medulla is composed of medullary cords and medullary sinuses (see Figs. 13.36 and 13....
Vasculature (Blood Vessels, Lymphatic Vessels, and Lymphatic Sinuses). The blood vessels of the lymph node include arteries, art...
Spleen
Red Pulp. Within the red pulp, macrophages are in the marginal sinus, PAMS, and attached to the reticular walls of the red pulp ...
White Pulp. White pulp consists of PALS, each with a splenic lymphoid follicle surrounded by a marginal zone. Normally these foc...
Red Pulp Vascular Spaces (Storage or Defense Spleens). Spleens are also classified as either storage or defense spleens, based o...
Hematopoietic Tissue. In the developing fetus, the liver is the primary site of hematopoiesis, with the spleen making a minor co...
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Dysfunction/Responses to Injury
Lymph Nodes
Sinus Histiocytes (Monocyte-Macrophage System). Sinus histiocytes (macrophages) are part of the monocyte-macrophage system and t...
Cortex (Lymphoid Follicles). Follicular hyperplasia of the cortex is discussed in the section Lymphoid/Lymphatic System, Lymph N...
Paracortex. Paracortical atrophy may result from a variety of causes, including deficiency in lymphocyte production in the bone ...
Medulla (Medullary Sinuses and Cords). Responses to injury by the medullary sinuses are dilatation of the sinuses and proliferat...
Spleen
Red Pulp (Monocyte-Macrophage System). The distribution and function of macrophages in the spleen is described earlier in the se...
Red Pulp (Vascular Spaces). The main response to injury of the red pulp vascular spaces is congestion (see the section on Lympho...
White Pulp. The responses to injury within the white pulp are most pronounced in the splenic lymphoid follicles. Lymphoid follic...
Capsule and Trabeculae. Lesions in the capsule and trabeculae are uncommon and include splenic capsulitis secondary to peritonit...
Thymus
Atrophy. Because the thymus does not contain any lymphopoietic tissue, it depends on the bone marrow for the supply of progenito...
Inflammation. Inflammation of the thymus is rare. Neutrophils and macrophages are often present within keratinized Hassall’s cor...
Hemorrhage and Hematomas. Thymic enlargement is often the result of hemorrhage, hematomas, or neoplasia and is discussed further...
Wasting/Cachectic Diseases. Any chronic disease, such as starvation, systemic neoplasia, and malabsorption syndrome, may produce...
Aging Changes of the Thymus. As part of the general aging change of cells as the body ages, there is reduction in the number of ...
Neoplasia. Primary tumors of the thymus are thymomas, arising from the epithelial component, and lymphomas and are discussed fur...
Mucosa-Associated Lymphoid Tissue
Hyperplasia. Hyperplasia of lymphoid nodules is a response to antigenic stimulation and consists of activation of germinal cente...
Atrophy. Atrophy of the diffuse lymphoid tissue and lymphoid nodules has the same causes as atrophy affecting other lymphoid tis...
Hemal Nodes
Portals of Entry/Pathways of Spread
Lymph Nodes
Spleen
Thymus
Mucosa-Associated Lymphoid Tissue
Hemal Nodes
Defense Mechanisms/Barrier Systems
Lymph Nodes
Spleen
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Diseases Affecting Multiple Species of Domestic Animals
Lymph Nodes
Pigmentation of Lymph Nodes. Red discoloration is caused by (1) draining erythrocytes from hemorrhagic or acutely inflamed areas...
Spleen
Congenital Disorders. Asplenia or the failure of a spleen to develop in utero occurs rarely in animals, and the effect on the an...
Disorders with Enlarged Spleens (Splenomegaly). Gross examination of the spleen involves deciding whether the spleen is enlarged...
E-Appendix 13.2 Methods of Gross and Microscopic Examination
Thymus
Spleen
Lymph Nodes
Microscopic Examination
Thymus
Congenital Disorders. Congenital disorders of the thymus are discussed in detail in Chapter 5, Diseases of Immunity. Thymic cyst...
Inflammatory and Degenerative Disorders. Thymitis is an uncommon lesion and may be seen in Postweaning Multisystem Wasting Syndr...
Thymic Hyperplasia. Asymptomatic hyperplasia may occur in juvenile animals in association with immunizations and results in symm...
Thymic Neoplasia. Because the thymus has both lymphoid and epithelial components, neoplasms may arise from either component. Thy...
Thymic Aging. As part of the general effects of aging in cells (see Chapter 1, Mechanisms and Morphology of Cellular Injury, Ada...
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Diseases of Horses
Severe Combined Immunodeficiency. SCID of Arabian foals is an autosomal recessive primary immunodeficiency disorder characterize...
Strangles. Streptococcus equi ssp. equi, the etiologic agent of equine strangles, is inhaled or ingested after direct contact wi...
Rhodococcus equi Infection. The typical manifestation of R. equi infection is chronic suppurative bronchopneumonia with abscesse...
Lymphoma. Lymphoma is the most common malignant neoplasm in horses and mostly affects adult animals (mean age 10 to 11 years) wi...
Spleen
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Diseases of Ruminants (Cattle, Sheep, and Goats)
Johne’s Disease. Johne’s disease primarily affects domestic and wild ruminants (and rarely pigs and horses) and is due to infect...
Bovine Viral Diarrhea. Bovine viral diarrhea (BVD) is caused by BVDV, a pestivirus. Cattle are the natural host, but other anima...
Caseous Lymphadenitis. C. pseudotuberculosis is a Gram-positive intracellular bacterium that causes caseous lymphadenitis, a chr...
Lymphoma. Bovine lymphoma is broadly classified into enzootic and sporadic forms. The enzootic form, called enzootic bovine leuk...
Spleen
Anthrax. B. anthracis, the causative agent of anthrax, is a Gram-positive, large, endospore-forming bacillus, which grows in aer...
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Bovine Viral Diarrhea. See the section on Lymphoid/Lymphatic System, Diseases of Ruminants (Cattle, Sheep, and Goats), Lymph Nod...
Hemal Nodes
Diseases of Pigs
Postweaning Multisystem Wasting Syndrome. PCV2, a small single-stranded DNA virus, is highly prevalent in the domestic pig popul...
Porcine Reproductive and Respiratory Syndrome. Porcine reproductive and respiratory syndrome (PRRS) is caused by an arterivirus ...
Porcine Jowl Abscess. Streptococcus porcinus causes jowl abscesses in pigs. The bacteria colonize the oral cavity and spread to ...
Lymphoma. Lymphoma is the most frequently reported cancer of pigs based on abattoir surveys. Affected pigs are typically less th...
Spleen
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Diseases of Dogs
Histoplasmosis. Histoplasma capsulatum can cause a disseminated fungal disease that is widely endemic, particularly in areas wit...
Leishmaniasis. Leishmaniasis is a disease of the monocyte-macrophage system caused by protozoa of the genus Leishmania. It occur...
Canine Distemper. Canine distemper virus preferentially infects lymphoid, epithelial, and nervous cells (see Chapter 14, Nervous...
Canine Parvovirus. Canine parvovirus type 2 (CPV-2) is a highly contagious disease of dogs spread through the fecal-oral route o...
Lymphoma. Fig. 13.90 and E-Figs. 13.17 and 13.18 show the cytologic and histopathologic features of commonly diagnosed lymphomas...
T Zone Lymphoma. TZL is the most common indolent lymphoma in dogs (see Fig. 13.90, C, and E-Fig. 13.19). It presents as a solita...
Marginal Zone Lymphoma. MZL is an indolent B lymphocyte neoplasm derived from the cells of the marginal zone of lymphoid follicl...
Plasmacytomas. See Lymphoid/Lymphatic System, Diseases Affecting Multiple Species of Domestic Animals, Lymph Nodes, Neoplasia, P...
Spleen
Splenic Fibrohistiocytic Nodules. The entity splenic fibrohistiocytic nodule (SFHN), first described in 1998, is not a single co...
Lymphoid and Complex Splenic Nodular Hyperplasia. Splenic nodular hyperplasia is common in dogs and grossly is characterized by ...
Histoplasmosis. See the section on the Lymphoid/Lymphatic System, Diseases of Dogs, Lymph Nodes and the section on Lymphoid/Lymp...
Hemangiosarcoma. See the section on Lymphoid/Lymphatic System, Diseases Affecting Multiple Species of Domestic Animals, Disorder...
Severe Combined Immunodeficiency Disease. See the section on the Lymphoid/Lymphatic System, Diseases of Dogs, Thymus
Thymus
Combined Immunodeficiency Diseases. Several types of SCIDs have been described in dogs. A mutation in DNA-PKcs (similar to Arabi...
Canine Parvovirus. See the section in this chapter on the Lymphoid/Lymphatic System, Diseases of Dogs, Lymph Nodes
Thymic Hematomas. Thymic hemorrhage and hematomas have been reported in dogs and are most often seen in young animals. A variety...
Mucosa-Associated Lymphoid Tissue (MALT)
Canine Parvovirus. See the section on Lymphoid/Lymphatic System, Diseases of Dogs, Lymph Nodes. Also see Lymphoid/Lymphatic Syst...
Hemal Nodes
Diseases of Cats
Feline Panleukopenia (Parvovirus). Feline panleukopenia, caused by the single-stranded DNA virus FPV, is a highly contagious and...
Lymphoma. Lymphoma is the most commonly diagnosed neoplasm in cats (Fig. 13.92 and E-Figs. 13.22 and 13.23), and the incidence i...
Mast Cell Tumors. See Bone Marrow and Blood Cells, Diseases Affecting Multiple Species of Domestic Animals, Hematopoietic Neopla...
Spleen
Thymus
Mucosa-Associated Lymphoid Tissue (MALT)
Hemal Nodes
Bone. The bone marrow is supported by an anastomosing network of trabecular bone that radiates centrally from the compact bone o...
Reticular Cells (Fibroblasts). Within the marrow spaces, a network of stromal cells and extracellular matrix provides metabolic ...
Adipose Tissue (Adipocytes). Marrow adipocytes store or provide energy, secrete adipose-derived hormones, termed adipokines, and...
Blood Vessels and Endothelium. Bone marrow is highly vascularized but does not have lymphatic drainage. Marrow of long bones rec...
14 - Nervous Systema
Central Nervous System
Structure and Function
Neurons
Axonal Transport (Axoplasmic Transport). Axonal transport is a cellular mechanism used to move synaptic vesicles; proteins such ...
Membrane Potentials and Transmitter/Receptor Systems. A fundamental activity of neurons is to modulate and effectively transmit ...
Astrocytes
Regulation of the Microenvironment. The microenvironment of the CNS must be under strict control to maintain normal function. As...
Repair of Injured Nervous Tissue. In the CNS, reparative processes that occur after injury, such as inflammation and necrosis, a...
Structural Support of the CNS. Structurally, astrocytic processes provide support for other cellular elements and ensheathe and ...
Oligodendroglia
Microglia
Ependyma (Including Choroid Plexus Epithelial Cells)
Meninges
Endothelium
Vasculature of the CNS. The arterial vasculature transports and delivers its cellular- and plasma-based components between and a...
Rete mirabile. A rete mirabile (pl. retia mirabilia) is a network of blood vessels that functions as a vascular “countercurrent ...
Dysfunction/Responses to Injury
Concepts in Understanding Injury in the CNS
Neurons
Neuronal Cell Death. Neurons can die after injury as a result of one of two mechanisms: apoptotic cell death or necrotic cell de...
Apoptotic Cell Death (Programmed Cell Death). Apoptosis is a single cell-initiated, gene-directed, and self-destructive regulato...
Necrotic Cell Death. In contrast to apoptosis, necrosis usually affects groups of cells and elicits an inflammatory response. It...
Acute Neuronal Necrosis. Acute neuronal necrosis (also sometimes referred to as acidophilic or ischemic necrosis) is a common re...
Chronic Neuronal Loss (Brain Atrophy). Neuronal death and loss of neurons can occur as a result of progressive disease processes...
Wallerian Degeneration and Central Chromatolysis. Injury to axons of the CNS and PNS can result from a variety of causes, includ...
Astrocytes
Oligodendrocytes
Ependymal Cells
Microglia
Meninges
Vascular Responses to Injury
Infarction. Infarction means necrosis of a tissue after reduction of its arterial blood supply (ischemia). The rate at which isc...
Aging Changes
Portals of Entry/Pathways of Spread
Direct Extension
Hematogenous Entry
Leukocyte Trafficking
Retrograde Axonal Transport
Defense Mechanisms/Barrier Systems
Blood-Brain Barrier
Glia Limitans
Blood–Cerebrospinal Fluid Barrier
Cerebrospinal Fluid–Brain Barrier (Ependymal Barrier)
Innate and Adaptive Immune Responses
Inflammation of the CNS. Inflammation of the CNS is different from inflammation in other organs because of the presence of the b...
Hydrocephalus. By far the most common congenital CNS abnormality identified in domestic animals is hydrocephalus. It has a varie...
E-Appendix 14.1 Necropsy
Difficulties in the Examination of the Central Nervous System
Necropsy Procedures
Gross Examination before Fixation
Tissue Fixation
Other Considerations
Neural Tube Closure Defects (Dysraphia). Dysraphia means an abnormal seam, and these anomalies result from defective interaction...
Infectious Diseases
Viruses. The viruses causing CNS disease in domestic animals are listed in Table 14.3
E-Appendix 14.2 Infectious Diseases
Diseases Affecting Multiple Species of Domestic Animals
Borna Disease
Louping Ill
Japanese Encephalitis
Diseases of Ruminants (Cattle, Sheep, and Goats)
Sporadic Bovine Encephalomyelitis
Diseases of Pigs
Classical Swine Fever
Enterovirus-Induced Porcine Polioencephalomyelitis
Hemagglutinating Encephalomyelitis Viral Infection of Pigs
Fungi. A variety of fungi infect the CNS of animals. Potential pathogens include Aspergillus, Candida, Cryptococcus neoformans, ...
Degenerative Disorders
Aminoacidopathies. Two disorders characterized by errors of amino acid metabolism have been described in neonatal calves. One di...
Cerebral Cortical Atrophy. Brain atrophy caused by the loss of neurons in the cerebral cortex can occur in all animal species an...
Channelopathies. Channelopathies are a newly emerging group of inherited neuromuscular disorders of human beings that affect the...
Degenerative Leukomyelopathies. Degenerative leukomyelopathies are a heterogeneous group of familial, likely inherited, and acqu...
Epileptic Brain Damage. Brain damage caused by prolonged (usually >30 minutes) convulsive seizures (status epilepticus) is not w...
Hepatic Encephalopathy. Acute and chronic liver failure, as well as hepatic atrophy associated with congenital or acquired vascu...
Mitochondrial Encephalopathies. In human beings, various encephalopathic and myopathic syndromes caused by point mutations in mi...
Primary Neuronal Degeneration. Primary neuronal degeneration that occurs in many or all animal species is discussed in this sect...
Multisystem Neuronal Degeneration. Multisystem neuronal degeneration is discussed in sections covering CNS disorders unique to s...
Primary Cerebellar Neuronal Degeneration. Depending on the degree of maturation of the cerebellum and related systems at the tim...
Neuroaxonal Dystrophy. Disorders associated with axonal swellings (axonal spheroids) have been termed neuroaxonal dystrophy. Dis...
Motor Neuron Disorders. Motor neuron disorders have been described predominately in dogs, cats, cows, horses, and pigs. Degenera...
Nutritional Disorders
Vitamin B1 (Thiamine) Deficiency. Thiamine pyrodiphosphate is the active form of thiamine. It is a critical cofactor for several...
Vitamin A Deficiency. See the section on the Peripheral Nervous System, Diseases Affecting Multiple Species of Domestic Animals,...
Toxicoses
Chemicals. Chemicals used in the agricultural, industrial, and pharmaceutical industries can injure nerves by interfering with a...
Organotins
Circulatory Disturbances
Atherosclerosis. Atherosclerosis is reported in a variety of animals, including pigs, dogs, and several avian species. Older pig...
Nonlipid Vascular Changes. Arterial fibrosis occurs more frequently in older animals and has been described in dogs and horses. ...
Cerebral Edema (Permeability Changes). The causes and mechanisms of cerebral edema are presented in the section on vasogenic, cy...
Ischemic Myelopathy (Fibrocartilaginous Embolic Myelopathy). Fibrocartilaginous embolic myelopathy has been described in almost ...
Lysosomal Storage Diseases
Globoid Cell Leukodystrophy. As discussed previously, lysosomal storage generally refers to a cellular alteration in which an in...
Processes Affecting Myelin Formation and Maintenance
Hypomyelinogenesis and Dysmyelination. Disorders of myelin formation include hypomyelinogenesis (hypomyelination) and dysmyelina...
Spongy Degeneration (Status Spongiosus). Spongy degeneration is a group of disorders of young animals characterized by a moth-ea...
Demyelination. Demyelination, which means degeneration and loss of myelin already formed, can be divided into primary and second...
Infectious Disease. A small number of viruses are known to cause primary demyelination. Examples in animals include CDV and the ...
Immune-Mediated Disorders. Naturally occurring immune-mediated demyelination is rare in domestic animals. The best example is ca...
Traumatic Injury
Concussion. A concussion is a brain injury that results in a temporary loss of function, and this type of injury is common in hu...
Contusion. Contusion means bruising, which is associated with rupture of blood vessels. Injuries producing contusions are genera...
CNS Hemorrhage. Although hemorrhage can be caused by a wide variety of injuries, trauma is the most common cause (Box 14.11 list...
Compressive Injury. Compressive injuries can affect the brain, spinal cord, or both concurrently. In the brain, lesions such as ...
Brain Displacements. See the section on Central Nervous System, Dysfunction/Responses to Injury, Vascular Responses to Injury, C...
Cervical Stenotic Myelopathy. Cervical stenotic myelopathy, or wobbler syndrome, is characterized by stenosis of the cervical ve...
Neoplasia
Embryonal or Primitive Neoplasms. Considering the complexities of brain development and the fact that astrocytes and oligodendro...
Gliomas. There have long been attempts to favorably compare canine glioma with their human counterparts, which has led to the us...
Ependymomas. Ependymomas are most common in the cat and much less frequently observed in other species, including dogs, cattle, ...
Choroid Plexus Tumors. Choroid plexus tumors (papillomas and carcinomas) occur most commonly in the dog but have been reported i...
Meningiomas. Meningiomas are the most common neoplasm of the CNS in dogs (representing ∼50% of all primary intracranial neoplasm...
Metastatic Tumors. Hematogenously metastasizing neoplasms occur and affect the brain more often than the spinal cord. The specie...
Miscellaneous Conditions
Meningeal Melanosis (Congenital). The leptomeninges of animals and human beings with heavily pigmented skin, especially black-fa...
Diseases of Horses
Equine Encephalomyelitis
West Nile Viral Encephalomyelitis
Equine Herpesvirus 1 Myeloencephalopathy
Equine Protozoal Encephalomyelitis (Sarcocystosis)
Halicephalobus gingivalis
Equine Degenerative Myeloencephalopathy, Neuroaxonal Dystrophy, and Equine Motor Neuron Disease
Primary Cerebellar Neuronal Degeneration
Leukoencephalomalacia
Centaurea spp. Poisoning
Cholesteatomas
Peripartum Asphyxia Syndrome
Postanesthetic Myelopathy
Diseases of Ruminants (Cattle, Sheep, and Goats)
Listeriosis
Thrombotic Meningoencephalitis
Bovine Malignant Catarrhal Fever
Bovine Alphaherpesvirus Meningoencephalitis
Schmallenberg Virus
Other Bunyavirus Diseases
Astrovirus
Visna
Caprine Arthritis Encephalitis
Sporadic Bovine Encephalomyelitis
Bovine Spongiform Encephalopathy
Ovine Spongiform Encephalopathy (Scrapie)
Primary Cerebellar Neuronal Degeneration
Thiamine Deficiency in Ruminants
Copper Deficiency
Clostridium perfringens Type D Encephalopathy (Pulpy Kidney Disease, Overeating Disease)
Diseases of Pigs
Enterovirus-Induced Porcine Polioencephalomyelitis
Hemagglutinating Encephalomyelitis
Pseudorabies
Classical Swine Fever (Hog Cholera)
Edema Disease (Enterotoxemic Colibacillosis)
Diseases of Dogs
Canine Distemper
Old-Dog Encephalitis
Canine Herpesvirus
Degenerative Myelopathy
Canine Multiple System Degeneration
Multisystem Neuronal Degeneration of the Red-Coated English Cocker Spaniel
Multisystemic Neuronal Degeneration of the Cairn Terrier
Primary Cerebellar Neuronal Degeneration
Neuronal Vacuolation and Spinocerebellar Degeneration
Thiamine Deficiency in Carnivores
Chiari-like Malformation
Dural Ossification
Inherited Necrotizing Myelopathy of Afghan Hounds
Granulomatous Meningoencephalitis
Necrotizing Encephalitides
Other Immune-Mediated Diseases
Intervertebral Disk Disease
Aging Changes
Diseases of Cats
Feline Infectious Peritonitis
Feline Ischemic Encephalopathy
Peripheral Nervous System
Structure and Function
Dysfunction/Responses to Injury
Responses of the Axon to Injury
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Blood-Nerve Barrier
Diseases Affecting Multiple Species of Domestic Animals
Congenital/Hereditary/Familial Disorders
Ganglioradiculitis
Dysautonomias
Peritonitis-Induced Autonomic Dysfunction
Myelination Disorders
Endocrine Disorders
Nutritional Disorders
Toxic Disorders
Autoimmune Disorders
Myasthenia Gravis. Myasthenia gravis is a disorder of neuromuscular impulse transmission at myoneural junctions that results in ...
Infectious Diseases
Viruses and Protozoa. Inflammation caused by infectious agents is relatively uncommon in the PNS, but some viral and protozoal i...
Lysosomal Storage Disorders
Globoid Cell Leukodystrophy. Peripheral nerves may be affected in globoid cell leukodystrophy, and lesions are characterized by ...
Traumatic Injury
Neurogenic Shock. Neurogenic shock is caused by an alteration in the function of the autonomic nervous system and its regulation...
Neoplasms
Diseases of Horses
Colonic aganglionosis
Equine Grass Sickness (Equine Dysautonomia)
Equine Motor Neuron Disease
Equine Degenerative Myeloencephalopathy
Recurrent Laryngeal Paralysis
Diseases of Ruminants (Cattle, Sheep, and Goats)
Diseases of Pigs
Diseases of Dogs
Dysautonomias
Peritonitis-Induced Dysautonomias
Acute Idiopathic Polyneuritis
Neurogenic Cardiomyopathy (Brain-Heart Syndrome)
Diseases of Cats
Development of the Nervous System
15 - Skeletal Musclea
Function
Metabolism and Ionic Homeostasis
Examination of Muscle: Clinical, Gross, and Microscopic
Clinical Findings
Clinicopathologic Findings
Electromyography
Methods of Gross and Microscopic Examination of Muscle
Gross Examination of Muscle
Sampling of Muscle for Examination
Microscopic Examination
Enzyme Histochemistry and Immunohistochemistry
Electron Microscopy
Other Methods of Evaluation
Dysfunction/Responses to Injury
Necrosis and Regeneration
Alteration in Myofiber Size
Atrophy
Physiologic Muscle Atrophy. Decrease in myofiber diameter and therefore in the overall muscle mass is a physiologic response to ...
Atrophy Caused by Endocrine Disease. Preferential atrophy of type 2 fibers causing symmetric muscle atrophy also occurs because ...
Denervation Atrophy. Denervation atrophy, also known by the misnomer neurogenic atrophy, is not uncommon in veterinary medicine....
Atrophy Caused by Congenital Myopathy. Congenital myopathy in children is often associated with selective type 1 fiber atrophy. ...
Hypertrophy
Cytoarchitectural Changes
Vacuolar Change
Internal Nuclei
Whorled and Ring Fibers
Other Cytoarchitectural Changes
Chronic Myopathic Change
Aging
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Diseases Affecting Multiple Species of Domestic Animals
Types of Muscle Disease
Degenerative
Disturbance of Circulation. Given the numerous capillary anastomoses and rich collateral circulation of skeletal muscle, only di...
E-Appendix 15.1 Viral Causes of Myositis
Parasitic Myositides
Congenital and Inherited Myopathies
Congenital Muscular Hyperplasia (Double Muscling) in Cattle
Bovine Diaphragmatic Dystrophy
Ovine Muscular Dystrophy
Other Canine Muscular Dystrophies
X-linked Myotubular Myopathy
Other Muscular Diseases of Cattle
Myopathy of Gelbvieh Cattle
Brown Swiss Cattle Neuronopathy
Other Breed-Associated Diseases of Dogs
Canine Dermatomyositis
Myopathy of Bouvier des Flandres Dogs
Distal Myopathy of Rottweiler Dogs
Myopathy of English Springer Spaniels
Myopathy of Great Danes
Myoclonus in Wirehaired Miniature Dachshunds
Other Breed-Associated Diseases of Cats
Myotonia and Pseudomyotonia
Equine Species
Bovine Species
Feline Species
Metabolic Myopathies
Acid Maltase Deficiency (Glycogenosis Type II; Pompe’s Disease)
Myophosphorylase Deficiency (Glycogenosis Type V; McArdle Disease)
Phosphofructokinase Deficiency (Glycogenosis Type VII)
Feline Glycogenoses
Equine Mitochondrial Myopathy
Canine Mitochondrial Myopathies
Other Canine Metabolic Myopathies
Nutritional Deficiency. Myofibers are particularly sensitive to nutritional deficiencies that result in the loss of antioxidant ...
Toxic Myopathies. Livestock are the animals most prone to develop a degenerative myopathy from the ingestion of a toxin (see Tab...
Exertional Myopathies. The ionic and physical events associated with myofiber contraction can, under certain circumstances, pred...
Trauma. External trauma to muscle includes crush injury, lacerations and surgical incisions, tearing caused by excessive stretch...
Inflammatory Myopathies (Myositis, Myositides [Plural])
Bacterial. Bacterial infections of muscle are not uncommon, particularly in livestock (Table 15.4). Bacteria can cause suppurati...
Viral. Relatively few of these are recognized in veterinary medicine. Spontaneous ones are listed in Table 15.5. Gross lesions m...
Parasitic. Parasitic infections of the skeletal muscles of domestic animals are not uncommon and include protozoal organisms and...
Immune Mediated. Immunologically induced myositis, not associated with vascular injury, has been recognized primarily in the dog...
Congenital and Inherited Disorders
Anatomic Defects. Anatomic defects in skeletal muscle are apparent at birth or soon thereafter. These defects can be either gene...
Muscular Dystrophy. The term muscular dystrophy has been grossly misused in the veterinary literature. According to the definiti...
Congenital Myopathies. Those inherited disorders of muscle that do not qualify as anatomic defects, muscular dystrophy, myotonia...
Myotonia (Channelopathies). Myotonia is defined as the inability of skeletal muscle fibers to relax, resulting in spasmodic cont...
Metabolic Myopathies. Inherited disorders of muscle metabolism (see E-Box 15.1) are characterized by reduced muscle cell energy ...
Malignant Hyperthermia. Malignant hyperthermia (MH) is a condition characterized by unregulated release of calcium from the sarc...
Endocrine and Electrolyte Abnormalities
Neuropathic and Neuromuscular Junction Disorders
Neuropathic Disorders. There are many peripheral nerve disorders and a few motor neuron disorders that can lead to denervation a...
Neuromuscular Junction Disorders. The neuromuscular junction is a modification of the postsynaptic myofiber membrane. At the neu...
Neoplasia
Primary Muscle Tumors. Tumors with striated muscle differentiation are thought to arise from intramuscular pluripotential stem c...
Other Tumors Involving Skeletal Muscle. A variant of lipoma, known as infiltrative lipoma, is often located in skeletal muscle. ...
Diseases of Horses
Bacterial and Parasitic Myopathies
Clostridial Myositis (Malignant Edema; Gas Gangrene)
Corynebacterium pseudotuberculosis (Pigeon Fever)
Streptococcal-Associated Myopathies
Purpura Hemorrhagica. In this disease, muscle damage is not caused by the direct infection of the muscles but, rather, by an imm...
Streptococcal-Associated Rhabdomyolysis and Muscle Atrophy. A syndrome of severe acute rhabdomyolysis resulting in profound rapi...
Protozoal Myopathy
Ear Tick–Associated Muscle Spasms
Nutritional and Toxic Myopathies
Nutritional Myopathy
Ionophore Toxicity
Plant Toxicities
Inherited or Congenital Myopathies and Myotonic Disorders
Hyperkalemic Periodic Paralysis
Equine Polysaccharide Storage Myopathy
Glycogen Branching Enzyme Deficiency
Myotonia and Mitochondrial Myopathy
Other Equine Myopathies
Exertional Rhabdomyolysis
Malignant Hyperthermia
Ischemic Myopathy
Postanesthetic Myopathy
Endocrine Myopathies
Denervating Diseases
Peripheral Neuropathy
Motor Neuronopathy
Diseases of Ruminants (Cattle, Sheep, and Goats)
Diseases of Cattle
Bacterial and Parasitic Myopathies
Clostridial Myositis (Blackleg). Clostridial myositis (blackleg), resulting from Clostridium chauvoei, is an extremely economica...
Botulism. Botulism caused by ingestion of Clostridium botulinum toxin from contaminated feed or soil occurs in cattle, and clini...
Pyogenic Bacteria. Cattle are prone to develop abscesses and cellulitis (fasciitis) from infections with pyogenic bacteria, most...
Actinobacillus lignieresii (Wooden Tongue). Infection of oral tissue, particularly of the tongue musculature (see Figs. 7.51 and...
Actinomyces bovis (Lumpy Jaw). Actinomyces bovis frequently involves bones of the jaw, causing chronic granulomatous to pyogranu...
Protozoal Myopathies. Sarcocystis spp. forming intracytoplasmic cysts (see Fig. 15.26) is a common incidental finding that may e...
Nutritional and Toxic Myopathies
Nutritional Myopathy. Similar to horses, calves and young cattle are susceptible to nutritional myopathy caused by a selenium or...
Plant Toxicities. Cassia occidentalis (coffee senna, coffee weed) is the most common cause of degenerative myopathy in cattle as...
Ionophore Toxicity. The pathogenesis of ionophore toxicity is discussed in the toxic myopathy section. Ionophore toxicity in cat...
Congenital or Inherited Disorders
Steatosis. Steatosis in cattle, sometimes called lipomatosis, is most often recognized as an incidental finding at necropsy or a...
Other Bovine Congenital or Inherited Myopathies and Neuronopathies. Congenital muscular hyperplasia (“double muscling”) resultin...
Electrolyte Abnormalities
Hypokalemic Myopathy. Decreased potassium interferes with normal muscle cell function and can lead to muscle weakness and myofib...
Other Electrolyte Abnormalities. Both hypocalcemia and hypophosphatemia can result in profound muscle weakness and recumbency in...
Ischemic Myopathy
Diseases of Sheep and Goats
Bacterial and Parasitic Myopathies
Clostridial Myositis (Blackleg). Clostridial myositis (blackleg) occurs occasionally in sheep and goats and is similar to the di...
Botulism. Botulism can occur in small ruminants, but, as in cattle, it is rare
Protozoal Myopathy. Intracytoplasmic cysts of Sarcocystis spp. are commonly found within skeletal and cardiac muscle fibers of s...
Nutritional and Toxic Myopathies
Nutritional Myopathy. Young goats and sheep are susceptible to degenerative myopathy associated with selenium or, less commonly,...
Toxic Myopathies. Sheep and goats are susceptible to plant and ionophore toxicities, similar to those in cattle. In goats, inges...
Congenital or Inherited Myopathies
Myotonia in Goats. Myotonia in the goat is inherited as an autosomal dominant trait, and the variable clinical severity is attri...
Other Inherited Myopathies. An inherited myopathy (ovine muscular dystrophy) in Merino sheep and an inherited glycogen storage m...
Megaesophagus in Camelids
Diseases of Pigs
Bacterial and Parasitic Myopathies
Clostridial Myositis (Malignant Edema)
Pyogenic Bacteria
Trichinosis
Protozoal Myopathies
Nutritional and Toxic Myopathies
Nutritional Myopathy
Toxic Myopathies
Congenital and Inherited Myopathies
Myofibrillar Hypoplasia (Splay Leg)
Steatosis
Malignant Hyperthermia (MH) (Porcine Stress Syndrome; Pale, Soft, Exudative Pork)
Muscular Dystrophy
Ischemic Myopathy
Diseases of Dogs
Parasitic Myopathies
Protozoal Myopathy
Other Parasites
Congenital or Inherited Myopathies
X-Linked Muscular Dystrophy (Duchenne’s Type)
Other Canine Muscular Dystrophies
Labrador Retriever Centronuclear Myopathy
X-linked Myotubular Myopathy
Congenital Myotonia
Swimmer Pups
Endocrine Myopathies
Hypothyroidism
Hypercortisolism
Immune-Mediated Myopathies
Polymyositis
Masticatory Myositis (Eosinophilic Myositis; Atrophic Myositis)
Extraocular Muscle Myositis
Disorders of the Neuromuscular Junction
Myasthenia Gravis
Tick Paralysis
Botulism
Other Canine Myopathies
Exertional Rhabdomyolysis
Malignant Hyperthermia
Other Breed-Specific Myopathies
Idiopathic Masticatory Muscle Atrophy
Denervating Diseases
Diseases of Cats
Inherited or Congenital Myopathies
X-Linked Muscular Dystrophy (Duchenne’s Type)
Other Feline Inherited or Congenital Myopathies
Electrolyte-Related Myopathies (Hypokalemia and Hypernatremia)
Immune-Mediated Disorders
Disorders of the Neuromuscular Junction
Myasthenia Gravis
Botulism
Denervating Diseases
Normal Skeletal Muscle
Structure of Myofibers
Types of Myofibers
Innervation and Motor Units
16 - Bones, Joints, Tendons, and Ligamentsa
E-Appendix 16.1
Postmortem Examination and Evaluation of Bones
Postmortem Examination and Evaluation of Joints
Intramembranous Ossification. Intramembranous ossification occurs primarily in mesenchyme derived from cranial neural crest cell...
Endochondral Ossification. Endochondral ossification occurs primarily in mesenchyme derived from somites (paraxial mesoderm) and...
Bone at the Cellular Level
Bone at the Organic Matrix and Mineral Level
Bone as a Tissue
Bone as an Organ
Blood Supply to Bone
Bone Growth
Joints
Articular Cartilage
Articular Capsule/Synovium/Synovial Fluid
Subchondral Bone
Tendons and Ligaments
Dysfunction/Responses to Injury
Bone
Joints
Articular Cartilage
Articular Capsule/Synovium/Synovial Fluid
Subchondral Bone
Tendons and Ligaments
Aging
Bone Aging
Tendons and Ligaments Aging
Summary
Portals of Entry/Pathways of Spread
Bone
Joints
Tendons/Ligaments
Defense Mechanisms/Barrier Systems
Bone
Joints
Tendons/Ligaments
Bone
Abnormalities of Growth and Development
Metabolic Bone Diseases
Osteoporosis. Osteoporosis is a disease in which bone fractures occur secondary to a reduction in bone density or mass (Fig. 16....
Rickets and Osteomalacia. Failure of mineralization with subsequent bone deformities and fractures is called rickets in the grow...
Fibrous Osteodystrophy. FOD is the name given to the skeletal lesions that result from primary hyperparathyroidism, secondary hy...
Inflammation
Infectious Inflammation. Inflammation of bone is termed osteitis. Periostitis is the appropriate term if the periosteum is invol...
Aseptic Necrosis
Proliferative and Neoplastic Lesions
Nonneoplastic Proliferative and Cystic Lesions. The nonneoplastic proliferative and cystic lesions considered here vary widely i...
Primary Neoplasms. There are many types of primary neoplasms involving the canine skeleton, the most common being composed of ce...
Secondary Neoplasms. At autopsy, 60% of human cancer patients have skeletal metastases. These metastases are predominantly in re...
Fracture Repair
Joints
Inflammatory Lesions
Arthritis. Neonatal bacteremia secondary to omphalitis or oral-intestinal entry commonly leads to polyarthritis in lambs, calves...
Noninfectious Arthritis. Noninfectious arthritis includes specific joint diseases that have inflammation as the initiating event...
Degenerative Joint Disease (DJD)
Degeneration of Intervertebral Disks
Neoplasms
Tendons and Ligaments
Neoplasms
Diseases of Horses
Diseases of Ruminants (Cattle, Sheep, and Goats)
Bone
Chondrodysplasias (Spider Lamb Syndrome [see Fig. 16.39]). See Diseases Affecting Multiple Species of Domestic Animals, Bone, Ab...
Joints
Arthrogryposis. Arthrogryposis refers to the congenital contracture of one or more joints, a condition that usually occurs with ...
Hip Dysplasia. See Diseases of Dogs, Joints, Abnormalities of Growth and Development, Hip Dysplasia
Diseases of Pigs
Bone
Diseases of Dogs
Bone
Metabolic Diseases
Renal Osteodystrophy. Renal osteodystrophy is a general term that refers to the skeletal lesions that develop secondary to chron...
Inflammation
Joints
Luxating Patella. A luxation is a complete dislocation of a joint, and a subluxation is a partial dislocation of a joint. Patell...
Hip Dysplasia. Hip dysplasia in dogs is a major orthopedic problem and occurs most commonly in large and giant breeds. It is inh...
Inflammatory Lesions
Diseases of Cats
Bone
Development of Bone
17 - The Integumenta
Function
Physical Barrier Function
Immune Defense
Thermoregulation
Metabolic Homeostasis
Environmental Communications
Sensory Perception
Dysfunction/Responses to Injury
Types of Clinical Skin Lesions
Claw Abnormalities
Diagnostic Procedures: Clinical Skin Lesions
Skin Biopsy Procedure
Patient Selection for Biopsy
Selection of Skin Lesions for Biopsy
Selection of Biopsy Site Based on the Type of Skin Lesion
Erosions and Ulcers. Biopsy erosions and ulcers at their margins to capture the edge of remaining epidermis and potential causes...
Tissue or Draining Tracts. Biopsy tissue or draining tracts in the center of the lesion with a wedge biopsy and retain the tract...
Macules and Patches. The preferred biopsy sites for macules and patches vary by the lesion type. Biopsy depigmented (leukodermic...
Leukotrichia. Biopsy leukotrichia (i.e., depigmented hair) in the center of recently developed lesions, which may be just inside...
Crusts. Biopsy crusts in the center of the lesion with a punch biopsy. Do not biopsy only crusts because most crusts are seconda...
Scaling Disorders. To identify scaling disorders, multiple punch biopsies (five or six samples) from the central most affected a...
Papules. Papules should be centered in the biopsy, usually a punch biopsy method is sufficient, and multiple biopsies (five or s...
Nodules, Plaques, and Masses. Large nodules, plaques, and masses are best sampled with one to two wedge biopsies at the margin o...
Vesicles, Bullae, and Pustules. For biopsy of vesicles, bullae, and pustules, the main goal is to collect these very fragile les...
Epidermal Collarettes. Avoid biopsy of epidermal collarettes because they are a characteristic lesion of superficial exfoliative...
Lichenification. Avoid biopsy of lichenification, which is always a secondary skin lesion and is not diagnostically specific. Us...
Atrophy. Biopsy regions of atrophy that involve the entire skin thickness (epidermis and dermis) in the central, most affected, ...
Alopecia. The key to biopsy alopecia is to capture enough affected hair follicles. To achieve this goal, first collect several (...
Mucinosis. Biopsy mucinosis in the central most affected areas multiple times using a punch biopsy. Samples can be fragile and c...
Pannicular and Subcutaneous Lesions. Always biopsy the centers of pannicular and subcutaneous lesions, because it is hard to hit...
Claws. The biopsy of claws is invasive and reserved for diseases that cannot be differentiated by other methods. In addition, cl...
Skin Biopsy Techniques
Artifacts
Skin Preparation
Tissue Fixation
History
Ancillary Procedures
Types (Patterns) of Histopathologic Skin Lesions
General Reaction Patterns
Epidermal Reaction Patterns. The epidermis responds to most types of injury (e.g., inflammatory, physical) and in wound repair i...
Pigment Reaction Patterns. Histologic reaction patterns involving pigments are limited. Hyperpigmentation is primarily an epider...
Pannicular Reaction Patterns. The noninflammatory reaction patterns of the panniculus (subcutis) are limited and not unique to t...
Inflammatory Reaction Patterns
Perivascular to Interstitial Dermatitis. In perivascular dermatitis, inflammatory cells localize around superficial, mid, and/or...
Cell-Mediated Cytotoxic Dermatitis. Cell-mediated cytotoxic dermatitis (interface dermatitis) presents either as an interface-pr...
Intraepidermal Vesicular/Pustular Dermatitis. Intraepidermal vesicles, bullae, and pustules are seen as variably sized cavities ...
Subepidermal Vesicular/Pustular Dermatitis. In this inflam­matory reaction pattern, the epidermis separates from the dermis, and...
Vasculitis and Vasculopathy. Vasculitis is inflammation of the blood vessel wall in association with vessel wall injury (see Tab...
Nodular and/or Diffuse Dermatitis. Nodular to diffuse dermatitis is recognized by the presence of discrete nodules and/or solid ...
Perifolliculitis, Folliculitis, and Adenitis. In these patterns, inflammation targets the adnexa, most commonly the hair follicl...
Panniculitis. Panniculitis is inflammation that involves the lobular adipose and/or connective tissue septa of the panniculus. I...
Atrophic and Fibrosing Dermatoses. Certain noninflammatory reaction patterns, such as atrophic dermatosis or fibrosing dermatosi...
Adnexal Reaction Patterns
Hair Follicle Reaction Patterns. The infundibulum of the hair follicle is contiguous with the interfollicular epidermis, shares ...
Glandular Reaction Patterns. Sebaceous gland hyperplasia is observed as increased size and number of sebaceous gland lobules and...
Regeneration and Repair
Healing of Wounds with Opposed Edges
Healing of Wounds with Separated Edges
Aging Changes
Portals of Entry/Pathways of Spread
Defense Mechanisms/Barrier Systems
Immunologic Defense Mechanisms
Innate Immunity
Acquired (Adaptive) Immunity
Skin as a Physical Barrier
Congenital and Inherited Disorders
Collagen Dysplasia
E-Appendix 17.1 Postmortem Evaluation of the Skin, Claws, Pawpads, and Hooves
E-Table 17.4
Congenital Alopecia and Hypotrichosis
Cornification Defects
Primary Idiopathic Seborrhea. Seborrhea is a clinical term that is used to describe excessive scaling of the skin. Seborrhea is ...
Ichthyosis. Ichthyoses encompass a heterogeneous group of inherited and generally congenital skin diseases with altered epiderma...
Congenital Inflammatory Linear Verrucous Epidermal Nevi
Congenital Lymphedema
Epidermolysis Bullosa (Red Foot Disease)
Disorders of Radiation, Chemical, or Physical Injury
Radiation Injury
Solar Injury. The sun emits three types of UVR that reach the earth: (1) long-wavelength UVA radiation (400 to 315 nm), (2) medi...
Ionizing Radiation Injury. Advances in the treatment of cancer in companion animals have made the possibility of radiation-induc...
Chemical Injury
Contact Dermatitis. Contact dermatitis results from chemicals that penetrate the protective layers of the skin that induce skin ...
Injection Site Reactions. Injections of vaccines or therapeutic drugs into the subcutis can incite an exaggerated local immunolo...
Envenomations: Snake Bites, Spider Bites, and Scorpion Stings. Envenomations occur regularly in animals with access to the outdo...
Selenium Toxicosis. Selenium is an essential element that has a narrow margin of safety. It is also an essential component of mo...
Ergot and Fescue Toxicity. Ergot toxicity (ergotism, ergot poisoning) affects cattle, sheep, and horses and is caused by the ing...
Physical Injury
Callus. A callus is a raised, irregular plaque of thickened skin that develops after repeated friction, pressure, or other irrit...
Intertrigo (Skin Fold Dermatitis). Intertrigo is a focal superficial dermatitis occurring on apposed skin surfaces, such as thos...
Hygroma. A carpal hygroma is an acquired bursa over the cranial/dorsal aspect of the carpus. It occurs in all animals and is cau...
Microbial and Parasitic Disorders
Viral Infections
Poxviruses. Poxviruses are a diverse group of large, nonenveloped, complex double-stranded DNA viruses that replicate in the cyt...
Herpesviruses. Herpesviruses are enveloped DNA viruses that can infect human beings and many animal species, including insects, ...
Papillomaviruses. Papillomaviruses are circular, nonenveloped, double-stranded DNA viruses with highly specific host- and tissue...
Other Viruses. Cutaneous lesions are seen with foot-and-mouth disease (picornavirus), vesicular stomatitis (rhabdovirus), swine ...
Bacterial Infections
Superficial Bacterial Infections (Superficial Pyodermas). Superficial bacterial infections (superficial pyodermas) involve the e...
Bacterial Granulomatous Dermatitis and Panniculitis (Bacterial Granulomas). Bacterial granulomatous dermatitis is usually caused...
Fungal (Mycotic) Infections
Superficial Mycoses. Superficial mycoses are infections restricted to the stratum corneum or the extrafollicular part of the hai...
Cutaneous Mycoses. Cutaneous mycoses (also considered as superficial mycoses by some dermatopathologists) are infections restric...
Subcutaneous Mycoses. Subcutaneous mycoses involve the dermis, subcutaneous tissues, muscle, and fascia. They are caused by usua...
Systemic Mycoses. Systemic mycoses include Blastomyces dermatitidis, Coccidioides immitis, Coccidioides boposadasii, Histoplasma...
Algal Infections
Parasitic Infections
Mites. Mite infestations can cause serious cutaneous lesions in domestic animals and economic loss in food animals. Mite infesta...
Ticks. Ticks comprise two families, Ixodidae (hard ticks that have a scutum [a hard chitinous plate on the anterior dorsal surfa...
Lice. Pediculosis is the term used to label infestation with lice. It is caused by two orders of lice: Mallophaga (biting lice) ...
Fleas. Two common species of fleas, the cat flea (Ctenocephalides felis) and the dog flea (Ctenocephalides canis), infest both d...
Flies. Cutaneous reactions caused by fly bites range from minor to severe and are caused by bites from adult flies and myiasis b...
Helminths. Cutaneous infections with helminths are generally not life threatening but can be unsightly and irritating in compani...
Protozoa. Cutaneous protozoal infections develop as part of systemic infections, principally with members of the genus Leishmani...
Immunologic Skin Disorders
Selected Hypersensitivity Reactions
Urticaria and Angioedema. Urticaria (hives) and angioedema occur most commonly in horses and dogs. Urticaria is characterized by...
Atopic Dermatitis. Atopic dermatitis is defined as a genetically predisposed, inflammatory and pruritic, allergic skin disease w...
Eosinophilic Dermatitides. Eosinophils are involved in the inflammatory responses to foreign material, especially parasites, and...
Allergic Contact Dermatitis. Allergic contact dermatitis is an example of a type IV hypersensitivity reaction. It can occur in d...
Hypersensitivity Reactions to Drugs. Hypersensitivity reactions to drugs are uncommon in dogs and cats, are rare in other domest...
Nodular Granulomatous Disorders without Microorganisms
Sterile Pyogranulomatous Dermatitis and Panniculitis. Sterile pyogranulomatous dermatitis and panniculitis (idiopathic sterile g...
Xanthomas (Xanthogranulomas). Xanthomas are rare, usually multifocal yellow macules, papules, nodules or plaques in the skin ass...
Selected Pemphigus Complex Autoimmune Diseases
Pustular Acantholytic Autoimmune Diseases. The pemphigus complex of autoimmune diseases is mediated by autoantibodies and is cli...
Subepidermal Blistering Diseases (Bullous Dermatoses). Bullous dermatoses are a rare group of acquired autoimmune disorders that...
Vasculitis
Cold Agglutinin Disease
Adnexal Disorders
Noninflammatory Alopecia
Follicular Dysplasia (Inherited Alopecia/Hypotrichosis). The term “dysplasia” is defined as an abnormal development of tissues o...
Acquired Hair Cycle Disorders. Alopecic disorders with an acquired impaired hair cycle have been described mostly for dogs and a...
Alopecia Related to Trauma and Impaired Nutrition (Is­chemia). Traction alopecia in dogs and posttraumatic alopecia in cats are ...
Inflammatory Alopecia
Alopecia Areata. Alopecia areata is a T lymphocyte–mediated autoimmune disease that causes nonscarring hair loss. Lymphocytic in...
Lymphocytic Isthmic Mural Folliculitis. Lymphocytic isthmic mural folliculitis in dogs, cats, and horses may be observed as an i...
Granulomatous Degenerative Mural Folliculitis. Granulomatous degenerative mural folliculitis is a rare disorder and has been des...
Follicular Mucinosis. Follicular mucinosis is a rare skin disease and has been reported in dogs and cats. A relationship with pr...
Acne. Acne occurs in cats and dogs. The pathogenesis is unknown. A variety of causes (e.g., poor grooming habits, stress, underl...
Disorders Related to Nutrients
Malnutrition
Protein-Calorie Malnutrition
Zinc Deficiency/Zinc-Responsive Dermatosis. Zinc is intimately involved in cell division because it is involved in DNA replicati...
Copper Deficiency
Disorders of Pigmentation
Hypopigmentation
Inherited Hypopigmentation. Hereditary hypopigmentation occurs when genetic mutations alter any step involved in the development...
Acquired Hypopigmentation. Acquired ­depigmentation occurs with any disease that injures the epidermal melanin unit, either the ...
Hyperpigmentation
Cutaneous Manifestations of Systemic Disorders
Laminitis
Sepsis-Related or Inflammatory Laminitis. Sepsis-related or inflammatory laminitis is associated with bacterial toxins or other ...
Endocrinopathic Laminitis. The endocrinopathic form of laminitis is considered to arise from hormonal imbalances such as insulin...
Supporting or Contralateral Limb Laminitis. For contralateral or supporting limb laminitis, also referred to as laminopathy, lit...
Traumatic Laminitis. There are few detailed studies regarding traumatic laminitis. It occurs with intense training or excessive ...
Diagnosis of Laminitis. Diagnosis of laminitis is based on clinical, radiographic, and gross findings. Recent research suggests ...
Cutaneous Paraneoplastic Syndromes
Cutaneous Neoplasia
Diseases of Horses
Congenital and Inherited Disorders
Hereditary Equine Regional Dermal Asthenia
Chronic Progressive Lymphedema of Draft Horses
Viral Infections
Molluscum Contagiosum (Molluscipoxvirus)
Bacterial Infections
Proliferative Pododermatitis (Canker)
Necrotizing Pododermatitis (Thrush)
Parasitic Infections
Cutaneous Habronemiasis
Immunologic Skin Disorders
Insect Bite Hypersensitivity
Multisystemic Eosinophilic Epitheliotropic Disease of the Horse
Vasculitis
Purpura hemorrhagica. Purpura hemorrhagica (from Latin “purpura,” meaning purple) is the most commonly described cutaneous vascu...
Pastern Leukocytoclastic Vasculitis. Pastern leukocytoclastic vasculitis designates a vasculitis that is restricted to the dista...
Equine Pastern Dermatitis
Idiopathic Nodular Granulomatous Inflammatory Disorders
Equine Sarcoidosis. Equine sarcoidosis (equine idiopathic, generalized, or systemic granulomatous disease; equine histiocytic de...
Hyperesthetic Leukotrichia
Adnexal Disorders
Acquired Hypertrichosis in Horses
Miscellaneous Dermatologic Disorders
Equine Coronary Band Dystrophy
Diseases of Ruminants (Cattle, Sheep, and Goats)
Congenital and Inherited Disorders
Congenital Hypertrichosis
Hereditary Zinc Deficiency in Calves and Goats
Disorders of Radiation, Chemical, or Physical Injury
Vetch Toxicosis and Vetchlike Diseases
Viral Infections
Poxviruses
Cowpox. Cowpox virus (genus Orthopoxvirus, family Poxviridae) infections occur rarely in cattle in the United Kingdom and other ...
Bovine Papular Stomatitis. Bovine papular stomatitis is caused by bovine papular stomatitis virus (genus Parapoxvirus, family Po...
Capripoxviral Diseases. The genus Capripoxvirus (family Poxviridae) includes virus species causing disease in ruminants. Sheeppo...
Contagious Ecthyma. Contagious ecthyma (contagious pustular dermatitis, orf, sore mouth, scabby mouth) is a common, highly conta...
Herpesviruses
Bovine Herpesvirus-2. Bovine herpesvirus-2 (genus Simplexvirus, family Herpesviridae) can cause generalized disease (pseudo–lump...
Bovine Herpesvirus-4. Bovine herpesvirus-4 (genus Gammaherpesvirus, family Herpesviridae) is thought to cause ulcerative mammary...
Bacterial Infections
Ovine Fleece Rot (Superficial Bacterial Infection)
Papillomatous Digital Dermatitis (Bacterial Pododermatitis)
Interdigital Necrobacillosis of Cattle
Contagious Foot Rot/Benign Foot Rot in Cattle
Contagious Foot Rot in Sheep (Bacterial Pododermatitis)
Necrobacillosis of Sheep (Bacterial Pododermatitis)
Contagious Ovine Digital Dermatitis (Bacterial Pododermatitis)
Parasitic Infections
Filarial Dermatitis
Immunologic Skin Disorders
Vasculitis
Diseases of Pigs
Congenital and Inherited Disorders
Dermatosis Vegetans
Viral Infections
Swinepox
“Idiopathic Swine” Vesicular Disease
Classic Swine Fever (Hog Cholera)
Bacterial Infections
Exudative Epidermitis of Pigs (Greasy Pig Disease)
Erysipelas
Septicemic Infection with Salmonella sp., Pasteurella multocida, or Escherichia coli
Immunologic Skin Disorders
Vasculitis
Porcine Dermatitis and Nephropathy Syndrome. Porcine dermatitis and nephropathy syndrome (PDNS) is a systemic inflammatory disea...
Porcine Juvenile Pustular Psoriasiform Dermatitis (Pityriasis Rosea)
Porcine Ulcerative Dermatitis Syndrome
Diseases of Dogs
Congenital and Inherited Disorders
Mucinosis (Hereditary Cutaneous Hyaluronosis) of the Chinese Shar Pei Dog
Hyperkeratosis of Nasal Planum or Pawpads in Dogs
Zinc-Responsive Dermatosis
Familial Cutaneous Vasculopathy of German Shepherd Dogs
Schnauzer Comedo Syndrome
Lethal Acrodermatitis of Bull Terriers
Nodular Dermatofibrosis and Renal Disease in the Dog
Disorders of Radiation, Chemical, or Physical Injury
Acral Lick Dermatitis
Pyotraumatic Dermatitis (Acute Moist Dermatitis, “Hot Spots”)
Canine Interdigital Palmar and Plantar Comedones and Follicular Cysts
Bacterial Infections
Canine Exfoliative Superficial Pyoderma (Superficial Spreading Pyoderma)
Postgrooming Furunculosis
Mucocutaneous Pyoderma
Toxic Shock Syndrome
Infection with Rickettsia rickettsii
Parasitic Infections
Hookworm Dermatitis and Dermatitis Caused by Other Helminth Larva Migrans
Immunologic Skin Disorders
Cell-Mediated Cytotoxic Dermatitis
Interface Predominant Cytotoxic Dermatitis. Interface dermatitis is a histologic inflammatory reaction pattern that targets the ...
Eosinophilic Furunculosis of the Face in Dogs
Eosinophilic Dermatitis with Edema in the Dog
Uveodermatologic Syndrome (Vogt-Koyanagi-Harada–Like Syndrome)
Focal Metatarsal Fistulation
Symmetric Lupoid Onychodystrophy
Vasculitis
Dermatomyositis and Similar Disorders with Cutaneous and Vascular Lesions (Ischemic Dermatopathy). Dermatomyositis is an inherit...
Proliferative Thrombovascular Necrosis of the Pinna. Proliferative thrombovascular necrosis of the pinnae occurs rarely in dogs,...
Sterile Neutrophilic Dermatoses
Nodular Granulomatous Inflammatory Disorders without Microorganisms
Sebaceous Adenitis. Sebaceous adenitis is an immune-mediated disease that targets and destroys the sebaceous glands (primary seb...
Juvenile Sterile Granulomatous Dermatitis and Lymphadenitis (Juvenile Cellulitis, Juvenile Pyoderma, Puppy Strangles). Juvenile ...
Canine Reactive Histiocytosis. Canine reactive histiocytosis is a poorly understood proliferative disorder of activated dermal d...
Canine Langerhans Cell Histiocytosis. Canine Langerhans cell histiocytosis is a rare condition in dogs that seems to occur most ...
Adnexal Disorders
Follicular Dysplasia
Follicular Dysplasias of Presumed Neuroectodermal Origin. In this form of dysplasia, alterations in the structure and/or functio...
Acquired Alopecia Associated with an Impaired Hair Cycle
Hair Cycle Disorders of Endocrine Origin. Hair cycle disorders of endocrine origin are due to imbalances in hormones. They are a...
Hair Cycle Disorders of Unknown Cause. In this group of disorders, various entities with unknown causes and/or pathogenetic mech...
Traction Alopecia. Traction alopecia in dogs is the result of an impaired blood supply to hair follicles and adjacent skin witho...
Skin Disorders Related to Nutrients
Vitamin A–Responsive Dermatosis
Cutaneous Manifestations of Systemic Disorders
Superficial Necrolytic Dermatitis (Diabetic Dermatopathy, Hepatocutaneous Syndrome, Necrolytic Migratory Erythema, Metabolic Epi...
Pancreatic Panniculitis (Necrotizing Panniculitis)
Cutaneous and Renal Glomerular Vasculopathy of the Greyhound
Miscellaneous Dermatologic Disorders
Seborrheic Keratosis
Hypersomatotropism
Diseases of Cats
Disorders of Physical Injury
Feline Idiopathic Ulcerative Dermatitis
Feline Psychogenic Alopecia. Psychogenic alopecia (feline self-induced symmetric alopecia) occurs mostly but not exclusively in ...
Alopecia Associated with Hypersensitivity (Feline Hypersensitivity Dermatitis). Like in feline psychogenic alopecia, the clinica...
Alopecia Related to Trauma and Impaired Nutrition (Ischemia). Posttraumatic alopecia occurs in cats after trauma that results in...
Viral Infections
Cowpox Infection in Cats
Feline Herpesvirus Ulcerative Dermatitis
Giant Cell Dermatosis (Feline Leukemia Virus Infection)
Feline Calicivirus Infection
Feline Coronavirus Infection (Feline Infectious Peritonitis [FIP])
Bacterial Infections
Feline Leprosy
Fungal (Mycotic) Infections
Dermatophytic Pseudomycetoma
Immunologic Skin Disorders
Mosquito Bite Hypersensitivity in Cats
Eosinophilic Plaques
Feline Hypereosinophilic Syndrome
Plasma Cell Pododermatitis
Nodular Granulomatous Inflammatory Disorders without Microorganisms
Feline Progressive Histiocytosis. Feline progressive histiocytosis is a rare condition in middle-aged to older cats. This disord...
Vasculitis
Auricular Chondritis
Feline Proliferative and Necrotizing Otitis Externa
Disorders of Pigmentation
Lentigo Simplex
Cutaneous Manifestations of Systemic Disorders
Feline Paraneoplastic Alopecia. Feline paraneoplastic alopecia is a rapidly progressive disease associated with internal maligna...
Feline Exfoliative Dermatitis with or without Thymoma. Exfoliative dermatitis in cats is a skin disorder with large and adherent...
Miscellaneous Dermatologic Disorders
Feline Ceruminous Cystomatosis
Feline Hyperadrenocorticism
Epidermis
Epidermal Basement Membrane
Dermis
Blood Vessels, Lymphatic Vessels, and Nerves
Subcutis (Also Known as Panniculus, Hypodermis)
Adnexa
Hair Follicles
Types and Arrangement of Hair Follicles. In terrestrial mammals, hair follicles can be differentiated based on their morphologic...
Hair Follicle Morphogenesis. Hair follicle formation in the embryo requires interactions from ectodermal, mesodermal, and neuroe...
Hair Follicle Cycle. Lifelong recurrent hair growth is maintained by the hair follicle cycle (see Fig. 17.6) and is needed for r...
Arrector Pili Muscles
Sweat Glands
Sebaceous Glands
Specialized Structures
Anal Sacs and Ducts. Anal sacs are bilateral diverticula located between internal and external anal sphincter muscles in dogs an...
Hepatoid Glands. Hepatoid (i.e., circumanal or perianal) glands occur most commonly in the skin around the anus and are present ...
Hooves of Horses. Hooves of horses consist of the wall, sole, and frog (see Fig. 17.61). The hoof wall comprises three structura...
Claws of Dogs and Cats. The claws of dogs and cats surround and shield the distal phalanx and are complex hard cornified and res...
Skin Microbiome
18 - Female Reproductive System and Mammaea
Ovary
E-Appendix 18.1 Techniques Used to Examine the Female Reproductive System and Mammae
Uterine Tube
Uterus
Cervix
Cell Types of the Female Reproductive System
Ovary
Uterus
Vulva, Vagina, and Cervix
The Mammae
Mammary Development, Lactation, and Involution
Cell Types
Function
Female Reproductive System
Mammae
Dysfunction/Responses to Injury
Female Reproductive System
Placenta
Mammae
Portals of Entry/Pathways of Spread
Female Reproductive System
Ascending Infections
Hematogenous Infections
Direct Penetration
Descending Infections
Transaxonal Infections
Mammae
Defense Mechanisms/Barrier Systems
Female Reproductive System
Innate Immunity (Acute Inflammation)
Adaptive Immunity
Hormonal Influences on Innate and Adaptive Immunity
Mammae
Innate Immunity (Acute Inflammation)
Adaptive Immunity
Diseases Affecting Multiple Species of Domestic Animals
Female Reproductive System
Normal Sexual Development
Congenital Disorders of the Reproductive Tract. There are a large number of individual steps involved in sexual development and ...
Disorders of Sexual Development. The term “disorders of sexual development (DSD)” is now preferred and replaces previously used ...
Cysts. Minor or incidental disorders are myriad in the reproductive tract. Foremost of these are the numerous cysts and tubular ...
Disorders of Growth. More significant disorders include failure of the normal maturation, hypoplasia, or aplasia of parts of the...
Disorders of the Ovary
Neoplasms of the Ovary. There are three main groups of primary ovarian neoplasms in domesticated animals: germ cell, sex cord st...
Disorders of the Uterine Tubes
Salpingitis (Including Pyosalpinx). Salpingitis is inflammation of the uterine tube. Pyosalpinx is a pus-filled uterine tube. Bo...
Hydrosalpinx. Hydrosalpinx is a dilated and fluid-filled uterine tube. Obstruction of the uterine tube prevents normal fluid fro...
Ectopic Pregnancy. Ectopic pregnancy of human beings and nonhuman primates occurs when the conceptus develops outside the uterus...
Disorders of the Uterus
Inflammatory Disorders. Most uterine infections are the result of ascending infection when the cervix is open—at estrus, parturi...
Neoplasms. Uterine neoplasms are uncommon in domestic animals. Lymphoma, which affects multiple sites of the body, is a common n...
Disorders of the Cervix
Vulva and Vagina
Noninflammatory Disorders. Swelling of the vulva is normal during estrus. Excessive or persistent swelling is abnormal and occur...
Fetus and Placenta
Normal Pregnancy. Pregnancy begins at conception, and the product of conception is the conceptus. It begins as a fertilized ovum...
The Mammae
Diseases of Horses
Female Reproductive System
Ovary
Uterus
Cervix
Equine Coital Exanthema. Equid alphaherpesvirus 3 is the cause of equine coital exanthema. It is a herpesvirus disease of the vu...
Fetus and Placenta
Infectious Failure of Pregnancy
Bacterial Infections
Mammae
Diseases of Ruminants (Cattle, Sheep, and Goats)
Female Reproductive System
Inflammation. The most common and important uterine disease of cattle is postpartum endometritis, also known as postpartum uteri...
Vulva and Vagina
Granular Vulvitis. Many different microbes cause granular vulvitis in cattle. It begins as an acute vulvitis or as a subclinical...
Infectious Pustular Vulvovaginitis. Infectious pustular vulvovaginitis (IPV) of cattle is caused by BoHV-1, which is similar to ...
Fetus and Placenta
Failure of Pregnancy. The diagnostic process utilized to determine the cause of failure of pregnancy in ruminants is similar to ...
The Mammae
Mastitis of Cows
Source of Infection. Determining the source of infection of the mammae is very important in understanding the pathogenesis of ma...
Clinical Manifestations of Mastitis. Mastitis is divided clinically into severe (with or without necrosis), suppurative, and sub...
Mastitis of Sheep and Goats
Diseases of Pigs
Female Reproductive System
Vaginal and Vulval Hypertrophy. Toxicosis of pigs caused by the mycotoxin zearalenone found in Fusarium sp.–infected grain and c...
Fetus and Placenta
Failure of Pregnancy. The principles of diagnosis used in other species apply to pigs (the presence or absence of lesions, the p...
Mammae
Agalactia
Diseases of Dogs
Female Reproductive System
Vulva and Vagina
Vaginitis or Vulvitis. In bitches, so-called nonspecific vaginitis or vulvitis is common. The lesions range from acute vaginitis...
Vaginal Hyperplasia. Vaginal hyperplasia, hypertrophy, and/or prolapse of bitches is a common disease seen during the follicular...
Vaginal Polyps. Vaginal polyps are relatively common in older, usually intact bitches (see Fig. 18.26). They are often solitary,...
Canine Transmissible Venereal Tumor. Canine transmissible venereal tumor (CTVT) of dogs is transmitted at coitus by the transfer...
Smooth Muscle Tumors. Bitches develop single or multiple smooth muscle tumors (leiomyomas) of the vagina. These tumors usually o...
Carcinomas. Carcinoma of the vagina in bitches is a recognized entity. Some clearly arise from the urethra, especially when they...
Fetus and Placenta
Failure of Pregnancy. Very little is published in the peer-reviewed literature about failure of pregnancy in dogs. There is much...
Mammae
Mastitis. In dogs, mastitis occurs early in lactation or pseudopregnancy. Staphylococcus sp., Streptococcus sp., and Escherichia...
Neoplasms
Diseases of Cats
Female Reproductive System
Noninfectious Disorders
Fibroadenomatous Hyperplasia. Fibroadenomatous hyperplasia (mammary hypertrophy) is highly prevalent and is the most common dise...
Neoplasms
19 - Male Reproductive Systema
Cell Types
E-Appendix 19.1 Methods for Examining the Male Reproductive Tract
Spermatogenic cells. Spermatozoa are formed from germ (stem) cells by a process called spermatogenesis. Spermatogenesis occurs i...
Testicular Sustentacular (Sertoli) Cells. Testicular sustentacular (Sertoli) cells provide support, nutrients, hormones, and cyt...
Interstitial Endocrine (Leydig) Cells. Interstitial endocrine cells are essential for normal testicular function. They produce t...
Epithelial Lining Cells. The cells lining the various ducts, including the rete tubules, efferent ductules, and epididymal duct,...
Cells Forming Accessory Genital Glands. In the accessory genital glands (see the next section), storage of spermatozoa (particul...
The Accessory Genital Glands
The Penis and Prepuce
Function
The Scrotum and Contents
The Accessory Genital Glands
The Penis and Prepuce
Dysfunction/Responses to Injury
The Scrotum and Contents
The Accessory Genital Glands
The Penis and Prepuce
Portals of Entry/Pathways of Spread
The Scrotum and Contents
The Accessory Genital Glands
The Penis and Prepuce
Defense Mechanisms/Barrier Systems
Innate Immunity
Adaptive Immunity
Inflammation
The Scrotum and Contents
Blood-Testis Barrier
The Accessory Genital Glands
The Penis and Prepuce
Diseases Affecting Multiple Species of Domestic Animals
Normal Male Sexual Development
Testicular Descent. The testes and epididymides undergo descent from their original location to the scrotum. There are three mai...
Sex Chromosome Disorders of Sexual Development
XX Disorders of Sexual Development
XY Disorders of Sexual Development
XY SRY-Positive Testicular DSD and a Female Phenotype. Individuals with XY SRY-positive testicular DSD and a female phenotype we...
XY SRY-Positive Testicular DSD and Male Phenotype. The majority of congenital anomalies of the male reproductive tract is in oth...
Disorders of the Scrotum and Contents
The Scrotum
Vaginal Tunic
Testis and Epididymis
Reduced Testicular and Epididymal Size. Many disorders of sexual development result in a reduction in size or the absence of scr...
Testicular and Epididymal Enlargement. There are several disorders that result in testicular and epididymal enlargement. Foremos...
Spermatic Cord
Disorders of the Accessory Genital Glands
Ampullae of the Deferent Duct
Vesicular Glands
Prostate
Bulbourethral Glands
Disorders of the Penis and Prepuce
Disorders of Sexual Development
Hemorrhage and Penile Hematoma
Inflammation
Neoplasms
Diseases of Horses
The Scrotum and Contents
The Accessory Genital Glands
The Penis and Prepuce
Penile Squamous Cell Carcinoma
Penile Habronemiasis, Sarcoids, and Exuberant Granulation Tissue
Diseases of Ruminants (Cattle, Sheep, and Goats)
The Scrotum and Contents
Epididymitis
Varicocele
The Accessory Genital Glands
Vesicular Adenitis
The Penis and Prepuce
Penile Forced Deviation and Hematoma
Penile Fibropapilloma
Preputial Prolapse
Ovine Posthitis
Diseases of Pigs
The Scrotum and Contents
The Accessory Genital Glands
The Penis and Prepuce
Preputial Diverticulitis
Diseases of Dogs
The Scrotum and Contents
Infectious Epididymitis with Orchitis
Testicular Neoplasms
The Accessory Genital Glands
Prostate (Prostatic) Hyperplasia
Prostatic and Paraprostatic Cysts
Prostatitis
Carcinoma of the Prostate
The Penis and Prepuce
Canine Transmissible Venereal Tumor
Diseases of Cats
20 - The Eara
External Ear
Middle Ear
Tympanic Membrane (Tympanum)
Tympanic Cavity
Auditory Ossicles
Malleus. The largest of the ossicles is the malleus. The manubrium of the malleus is embedded in the tympanic membrane (see Fig....
Incus. The incus is a bicuspid-shaped bone that lies caudal and dorsal to the malleus. It has two crura, one designated as the s...
Middle Ear Muscles and Nerves
Auditory Tube (Eustachian or Pharyngotympanic Tube)
Internal Ear
Cochlea
Vestibular System
Histologic Evaluation of the Internal Ear
Dysfunction/Responses to Injury
E-Appendix 20.1 Histologic Evaluation of the Internal Ear
External Ear
Middle Ear
Myringitis
Healing of the Tympanic Membrane
Goblet Cell Metaplasia and Impaired Mucociliary Clearance
Periosteal Exostosis of the Tympanic Bulla
Formation of Aural Inflammatory Polyps
Horner Syndrome/Pourfour du Petit Syndrome
Internal Ear
Sensory Cell Degeneration/Death
Auditory Ossicular Chain Damage
Aging
Portals of Entry/Pathways of Spread
External Ear
Extension from the External Environment
Hematogenous Spread
Extension from the Middle Ear
Middle Ear
Extension through Perforation of the Tympanic Membrane
Ascension of the Auditory Tube
Extension via Degeneration of the Temporohyoid Joint
Extension via Erosion through the Tympanic Bulla
Migration along Vascular or Neural Pathways
Internal Ear
Extension from the Middle Ear
Hematogenous Spread
Migration along Vascular or Neural Pathways
Defense Mechanisms/Barrier Systems
External Ear
Integumentary Defenses
Epithelial Migration
Adnexa and Cerumen
Commensal Organisms
Osseous External Acoustic Meatus
Middle Ear
Mucociliary Apparatus
Surfactant
Auditory Tube–Associated Lymphoid Tissue (ATALT)
Commensal Microorganisms
Internal Ear
Petrous Portion of the Temporal Bone
Acoustic Reflex
Diseases Affecting Multiple Species of Domestic Animals
Auricular Agenesis/Aplasia
Auricular Hypoplasia
Auricular Malformations
Supernumerary Pinna or Polyotia
Cropped or Notched Ears
Atresia of the External Acoustic Meatus
Stenosis of the External Acoustic Meatus (Congenital Hypothyroidism)
Otognathia
Inflammation of the External Ear
Otitis Externa
Vascular Injury of the External Ear
Infarction
Hematomas
Parasitic Diseases of the External Ear
Ear Mite Infestations (Otoacariasis)
Otodectes Cynotis. Otodectes cynotis infests the external acoustic meatus of domestic and wild cats, dogs, and occasionally rumi...
Notoedres Cati. Notoedres cati is primarily a cat pathogen but can infest dogs, foxes, rabbits, and rarely human beings. Usually...
Raillietia Species. Raillietia spp. of mites occur most commonly in cattle, buffalo, and goats of nearly every continent. Cattle...
Psoroptes cuniculi. Psoroptic otoacariasis is most commonly caused by Psoroptes cuniculi, infesting sheep, goats, deer, horses, ...
Ticks
Rhipicephalus Species. The brown ear tick, Rhipicephalus appendiculatus, is found most commonly in southern and southeastern Afr...
Gulf Coast Ear Tick. Another tick that preferentially infests the ear is variably named the Gulf Coast tick or Gulf Coast ear ti...
Spinose Ear Tick. Otobius megnini, the “spinose ear tick,” has a broad host range, including ungulates, sheep, goats, cattle, ho...
Bacterial Diseases of the External Ear
Dermatophilosis (Streptothricosis)
Neoplasms of the External Ear
Miscellaneous Disorders of the External Ear
Pinnal Alopecia
Developmental Anomalies of the Middle Ear
Primary Ciliary Dyskinesia (Immotile Cilia Syndrome)
Inflammation of the Middle Ear
Otitis Media
Aural Inflammatory Polyps (Nasopharyngeal Polyps)
Neoplasms of the Middle Ear
Inflammation of the Internal Ear
Otitis Interna (Labyrinthitis)
Vestibular Disease of the Internal Ear
Hearing Loss and Deafness
Neoplasia of the Internal Ear
Endolymphatic Sac Tumors
Diseases of Horses
Developmental Anomalies
Dentigerous Cysts (Temporal Odontomatas, Periauricular Cysts)
Miscellaneous Disorders
Auricular Chondrosis
Temporohyoid Osteoarthropathy
Infectious Microorganisms. Otitis media causes ventral osteitis of the bone of the tympanic bulla, and because of proximity to t...
Degenerative Joint Disease. Thickening of the proximal stylohyoid and ankylosis of the temporohyoid joint can result from degene...
Aural Plaques (Aural Papillomatosis)
Guttural Pouch Disease
Diseases of Ruminants (Cattle, Sheep, and Goats)
Developmental Anomalies
β-Mannosidosis of Cattle and Goats
Parasitic Diseases
Stephanofilarial Otitis
Rhabditis Species Otitis
Neoplasms
Aural Melanomas of Angora Goats
Diseases of Pigs
Miscellaneous Disorders
Aural Chewing (Ear Chewing or Ear Cannibalism)
Ear Necrosis (Necrotic Ear Syndrome and Ulcerative Spirochetosis of the Ear)
Diseases of Dogs
Auricular Parasitic Dermatitis
Inflammation
Otitis Externa, Media, and Interna
Canine Leproid Granuloma
Chronic Otitis Media with Cholesterol Clefts (Cholesterol Granulomas)
Miscellaneous Disorders
Tympanokeratoma (Aural Cholesteatoma)
Craniomandibular Osteopathy
Mucoperiosteal Exostoses (Otolithiasis)
Diseases of Cats
Developmental Anomalies
Feline Lysosomal Storage–Induced Microtia
Inflammation
Otitis Externa, Media, and Interna
Auricular Chondritis (Relapsing Polychondritis)
Proliferative, Necrotizing Otitis Externa
Parasitic Diseases
Mammomonogamus auris
Miscellaneous Disorders
Acquired Folding of the Auricle
Feline Ceruminous Cystomatosis
Neoplasms
Squamous Cell Carcinoma
21 - The Eyea
Embryology
Eyelids and Conjunctiva
Eyelids
Conjunctiva
Cornea and Sclera
Uvea
Lens
Vitreous
Retina and Optic Nerve
Orbit
Dysfunction/Response to Injury
Eyelids and Conjunctiva
Eyelids
Conjunctiva
Cornea
Epithelial and/or Stromal Necrosis
Corneal Edema
Corneal Neovascularization
Corneal Degenerations and Depositions
Corneal Inflammation (Keratitis)
Nonspecific Chronic Keratitis with Epidermalization. Nonspecific chronic keratitis with epidermalization (cutaneous metaplasia) ...
Corneal Wound Healing. Skin has provided the model for most basic wound healing studies (see Chapter 3, Inflammation and Healing...
Uvea
Uveitis
Causes of Uveitis. Uveitis can be initiated by a wide array of infections, immune responses, and trauma. The response obviously ...
Consequences of Uveitis. The inflammatory reactions in the uveal tract mimic those in other organs for both acute and chronic pr...
Fibrovascular Proliferation and Neovascularization. Fibrovascular proliferation (neovascularization) is often considered separat...
Lens
Vitreous
Asteroid Hyalosis
Vitreal Hemorrhage
Retina and Optic Nerve
Retinal Detachment
Orbit
Portals of Entry/Pathways of Spread
Eyelids and Conjunctiva
Eyelids
Conjunctiva
Cornea
Uvea
Lens
Vitreous
Retina and Optic Nerve
Orbit
Defense Mechanisms/Barrier Systems
Eyelids and Conjunctiva
Eyelids
Conjunctiva
Cornea
Uvea
Blood-Aqueous Barrier
Anterior Chamber–Associated Immune Deviation
Lens
Vitreous
Retina and Optic Nerve
Blood-Retina Barrier
Orbit
E-Appendix 21.1 Postmortem Technique
Disorders of the Globe as a Whole
Glaucoma
Histologic Changes Associated with Glaucoma. The challenge for the pathologist is that many histologic changes that can be secon...
Pathogenesis of Glaucoma. Glaucoma represents a heterogeneous group of diseases. The exact pathogenesis for the characteristic r...
Aging
Disorders of the Eyelids and Conjunctiva
Developmental Anomalies
Eyelid Agenesis (Coloboma). There may be partial or complete absence of an eyelid. It occurs in all species but is most common i...
Premature Eyelid Separation. In carnivores, the eyelids are normally fused at birth (known as physiologic ankyloblepharon), whic...
Entropion and Ectropion. Conformational entropion is the inward rolling of the eyelid margin because of inadequate overall lengt...
Anomalies of Cilia: Trichiasis, Distichiasis, and Ectopic Cilia. Anomalies of cilia are prevalent in dogs, less so in horses, an...
Conjunctival Dermoid. Dermoid is uncommon, but is the most common conjunctival developmental. The bulbar conjunctiva is most com...
Acquired Eyelid Disorders
Acquired Conjunctival Disorders
Infectious Diseases. Onchocerciasis causes conjunctival and orbital disease in dogs, cats, and horses. The life cycle is likely ...
Neoplasms of the Eyelids and Conjunctiva
Meibomian Gland Neoplasms. Meibomian adenomas and epitheliomas are very common neoplasms and represent up to 70% of all canine e...
Conjunctival Squamous Cell Carcinoma. Squamous cell carcinoma of the conjunctiva occurs in all species but is most common in cat...
Granular Cell Tumor. Granular cell tumors can affect the eyelid of dogs at the medial canthus. The histologic features are simil...
Apocrine Cystadenoma. Apocrine cystadenomas (hidrocystomas) are benign lesions that affect the eyelids of cats, most often Persi...
Neoplasms of the Gland of the Third Eyelid. The vast majority of third eyelid gland neoplasms are adenocarcinomas; however, aden...
Conjunctival Melanocytic Neoplasms. Primary conjunctival melanocytic neoplasia occurs mostly in dogs and cats. In both species, ...
Conjunctival Vascular Neoplasms. Vascular neoplasms arise within the conjunctival lamina of dogs, cats, and horses. Hemangioma a...
Conjunctival Mast Cell Tumor. Conjunctival mast cell tumors in dogs present clinically as smooth, firm, and subconjunctival and ...
Conjunctival Papillomas. Benign squamous papillomas are frequent lesions of the bulbar conjunctiva of dogs. They are formed by p...
Conjunctival Lymphoma. Conjunctival lymphoma occurs sporadically in all species. The conjunctiva may be the primary site or may ...
Disorders of the Cornea and Sclera
Dermoid. Dermoid is uncommon, but is the only corneal anomaly that is reasonably prevalent. As with conjunctival dermoid, the le...
Acquired Corneal Disorders
Indolent Corneal Ulcers (Nonhealing/Persistent/Recurrent Ulcers, Spontaneous Chronic Corneal Epithelial Defects). Indolent corne...
Corneal Sequestrum. Corneal sequestrum is mainly a condition of cats but it also occurs in horses and dogs (Fig. 21.36; E-Fig. 2...
Suppurative Keratomalacia (“Melting Ulcer”). Neutrophils from the tear film and limbus can release lytic enzymes, and many organ...
Corneal Dystrophies and Depositions. Among the domestic animals, corneal dystrophies and depositions are most often seen in dogs...
Neoplasms of the Cornea and Sclera
Corneal Squamous Cell Carcinoma. Corneal squamous cell carcinoma occurs predominantly in dogs and horses. In dogs, lesions are m...
Limbal (Epibulbar) Melanocytic Neoplasia. Limbal (epibulbar) melanocytic neoplasia occurs in dogs and rarely in cats. Limbal mel...
Disorders of the Uvea
Uveal Developmental Anomalies
Iris Hypoplasia. Failure of ingrowth of the future iris epithelium results in iris hypoplasia, typically affecting only the stro...
Acquired Uveal Disorders
Idiopathic Lymphoplasmacytic Uveitis. Lymphoplasmacytic uveitis is the most frequent histologic pattern of uveitis. Lymphocytes ...
Bacterial endophthalmitis. Most cases of bacterial endophthalmitis are the result of penetrating trauma. Hematogenous spread of ...
Lens-Induced Uveitis. Lens-induced uveitis can be separated between phacolytic uveitis and phacoclastic uveitis. Phacolytic uvei...
Systemic Fungal, Algal, and Parasitic Diseases. Systemic mycoses, such as blastomycosis, cryptococcosis, histoplasmosis, and coc...
Iridociliary Cysts. Acquired cysts of the posterior iris or ciliary body epithelium occur sporadically in all species. Most ofte...
Neoplasms of the Uvea
Canine Uveal Melanocytic Neoplasms. In dogs, benign uveal melanocytomas are most common in the iris and ciliary body, typically ...
Ocular Melanosis. Ocular melanosis (pigmentary glaucoma) is a unique condition that must be distinguished from uveal melanocytom...
Feline Diffuse Iris Melanoma. Feline diffuse iris melanoma (FDIM) is the most common ocular neoplasm in cats. In most instances,...
Equine Intraocular Melanocytic Neoplasia. Equine intraocular melanocytic neoplasia (EIMN) is associated with equine cutaneous me...
Neuroectodermal Neoplasms. Neuroectodermal neoplasia is second only to melanocytic neoplasia in frequency. Most are iridociliary...
Schwannomas. Schwannomas (also termed spindle cell tumors of blue-eyed dogs or peripheral nerve sheath tumors) occur almost excl...
Metastatic Neoplasms. Neoplasms metastatic to the globe are much less frequent than primary ocular neoplasia. Lymphoma is the mo...
Disorders of the Lens
Developmental Anomalies of the Lens
Lens Luxation
Diabetic Cataract
Neoplasms of the Lens
Feline Posttraumatic Ocular Sarcoma. Feline posttraumatic ocular sarcoma (primary ocular sarcoma) (FPTOS) is the second most com...
Disorders of the Retina and Optic Nerve
Retinal Developmental Anomalies
Retinal Dysplasia. Retinal dysplasia is a general term denoting an abnormal retinal differentiation characterized by disorganize...
Optic Nerve Hypoplasia. Optic nerve hypoplasia may be unilateral or bilateral. Primarily documented in dogs, optic nerve hypopla...
Acquired Retinal Disease
Ischemic Retinopathies. Ischemic damage to the retina can be the result of occlusion of the retinal vessels or, more often, from...
Nutritional Retinopathies. Vitamin A deficiency as a cause for retinopathy has been reported in cattle, horses, and pigs receivi...
Toxic Retinopathies. Toxic injury to the retina is a rare event. Locoweed poisoning affects cattle, sheep, and horses. The ocula...
Retinitis
Neoplasms of the Retina and Optic Nerve
Ocular Astrocytomas. Ocular astrocytomas have only been described in dogs. Clinically, astrocytomas appear as a discrete mass in...
Orbital Meningiomas. Orbital meningioma (optic nerve men­ingioma, retrobulbar meningioma) is a disease of dogs. Clinically, orbi...
Disorders of the Orbit
Neoplasms of the Orbit
Canine Lobular Orbital Adenomas. Canine lobular orbital adenomas arise from the lacrimal gland located dorsally or zygomatic sal...
Hibernomas. Hibernomas are benign neoplasms of brown adipose tissue and occur as subconjunctival or orbital masses. Ocular hiber...
Diseases of Horses
Disorders of the Eyelids and Conjunctiva
Habronemiasis
Disorders of the Cornea and Sclera
Equine Fungal Keratitis
Eosinophilic Keratitis
Immune-Mediated Keratopathies
Disorders of the Uvea
Equine Recurrent Uveitis
Disorders of the Retina and Optic Nerve
Congenital Stationary Night Blindness
Proliferative Optic Neuropathy
Diseases of Ruminants (Cattle, Sheep, and Goats)
Disorders of the Eyelids and Conjunctiva
Infectious Bovine Keratoconjunctivitis
Infectious Bovine Rhinotracheitis
Disorders of the Uvea
Malignant Catarrhal Fever
Disorders of the Retina and Optic Nerve
Transmissible Spongiform Encephalopathies
Retinal Toxicity
Diseases of Pigs
Disorders of the Eyelids and Conjunctiva
Disorders of the Cornea and Sclera
Blue Eye Disease
Diseases of Dogs
Disorders of the Eyelids and Conjunctiva
Idiopathic Granulomatous Marginal Blepharitis
Prolapse of the Gland of the Third Eyelid
Nodular Granulomatous Episcleritis
Xanthogranuloma
Ligneous Conjunctivitis
Disorders of the Cornea and Sclera
Chronic Superficial Keratitis (Pannus)
Granulomatous Scleritis
Protozoal Keratitis
Disorders of the Uvea
Uveodermatologic Syndrome (Vogt-Koyanagi-Harada–like Syndrome)
Asymmetric Uveitis
Intraocular Xanthoma (Xanthogranuloma)
Disorders of the Retina and Optic Nerve
Collie Eye Anomaly
Oculoskeletal Dysplasia (Oculoskeletal Syndrome)
Canine Progressive Retinal Atrophy
Sudden Acquired Retinal Degeneration
Granulomatous Meningoencephalitis
Disorders of the Orbit
Orbital Extraocular Polymyositis
Diseases of Cats
Disorders of the Cornea and Sclera
Herpesvirus Keratitis
Eosinophilic Keratitis
Tropical Keratopathy (Florida Spots)
Acute Bullous Keratopathy
Disorders of the Uvea
Feline Lymphoplasmacytic Uveitis
Feline Infectious Peritonitis (FIP)
Disorders of the Retina and Optic Nerve
Inherited Retinal Dysplasias and Degenerations
Taurine Deficiency
Enrofloxacin/Fluoroquinolone Toxicity
III - Appendices, VeterinaryDiagnostic Pathology*
A - Communication, Collaboration, and Consultation in Veterinary Pathology
Relevant Clinical Information Shared Through Pathology Accession Forms
Essential Information Conveyed through Pathology Case Reports
Consultation and Collaboration toward Accurate Clinical Diagnosis
Diagnostic Clinicopathologic Correlation
Clinical, Gross, and Microscopic Findings Linked toward Diagnosis
Differential Diagnoses, Anomalies, Incidental Lesions, and Uncertainty
Recommendations for Additional Diagnostic Evaluation or Consultation
B - Photographic Techniques in Veterinary Pathology
Lighting
Specular Highlights
Backgrounds
C - Postmortem Examination (Autopsy) of Domestic Animal Speciesa
D - Recognition and Interpretation of Macroscopic (Gross) Lesions
E - Diagnoses in Veterinary Pathologya
F - General Principles of Tissue Fixation and Processing
G - Fixatives and Fixation
H - Fixation and Trimming of the Brain, Spinal Cord, and Nerves
I - Surgical Biopsies—Procurement, Processing, and Sectioning Artifactsa
J - Gross Examination and Infusion Fixation of the Lung
K - Necropsy Techniques by Organ Systema
Index