Practical Lung Pathology: Frequently Asked Questions

Aim and Scope
Preface
Contents
Part I: Neoplastic Lung Pathology
1: Bronchial Squamous Cell Papilloma Versus Squamous Cell Carcinoma
Case Presentation
Pathologic Diagnosis: Bronchial Squamous Cell Papilloma—Negative for Severe Dysplasia and Malignancy
Key Points
What Is the Differential Diagnosis for Bronchial Squamous Cell Papilloma?
How Do I Differentiate Bronchial Squamous Cell Papilloma from Papillary Squamous Cell Carcinoma?
Are Bronchial Squamous Papilloma and Squamous Cell Carcinoma Associated with Viral Infection?
Are There Radiographic Differences Between Bronchial Squamous Cell Papilloma and Papillary Squamous Cell Carcinoma?
What Are the Clinical and Epidemiologic Differences Between Bronchial Squamous Papillomas and Primary Lung Squamous Cell Carcinomas?
References
2: Pulmonary Hamartoma Versus Chondroid Neoplasms
Case Presentation
Pathologic Diagnosis: Pulmonary Hamartoma
What Is the Definition of a Pulmonary Hamartoma? What Are Its Clinical and Prognostic Features?
What Are the Radiographic Features of Pulmonary Hamartomas?
What Are the Pathologic Features of Pulmonary Hamartomas?
What Is the Differential Diagnosis for Pulmonary Hamartomas?
How Does One Differentiate a Predominately Chondroid Pulmonary Hamartoma from a Chondroid Neoplasm?
Are Either Chondromas or Pulmonary Hamartomas Associated with Other Conditions?
Are There Demographic Differences Between Patients with Pulmonary Chondroma and Patients with Hamartoma?
How Does One Differentiate Pulmonary Hamartoma from Chondrosarcoma?
References
3: Reactive Type II Pneumocyte Hyperplasia Versus Adenocarcinoma
Case Presentation
Final Pathologic Diagnosis: Reactive Type II Pneumocyte Hyperplasia in the Wedge Biopsy
Differentiation Features of Reactive Type II Pneumocyte Hyperplasia and Adenocarcinoma
Reactive Type II Pneumocyte Hyperplasia
Cytomorphology
Secondary Architectures
The Underlying Lung Injury, Background Stroma, and Inflammatory Cell Infiltrates
Ancillary Studies
References
4: Atypical Adenomatous Hyperplasia Versus Peribronchiolar Metaplasia
Case Presentation
Pathologic Diagnosis: Minimally Invasive Adenocarcinoma, Acinar Pattern with Associated Lepidic Component in the Right Middle Lobe, Multifocal Adenocarcinoma In Situ, and Atypical Adenomatous Hyperplasia (AAH) in the Right Lower Lobe
What Are the Radiographic Features of Atypical Adenomatous Hyperplasia, and How Do They Differ from Peribronchiolar Metaplasia?
What Are the Gross Pathologic Features of Atypical Adenomatous Hyperplasia and Peribronchiolar Metaplasia, and in What Gross Context Are They Found?
What Are the Microscopic Features of Atypical Adenomatous Hyperplasia and Peribronchiolar Metaplasia? Is Immunohistochemistry or Molecular Testing Useful to Distinguish these Entities from One Another?
References
5: Adenocarcinoma In Situ Versus Atypical Adenomatous Hyperplasia
Case 1
Clinical Presentation
Imaging Studies
Pathologic Findings
Gross Examination
Histologic Examination
Final Diagnosis: Adenocarcinoma in Situ (AIS)
Case 2
Clinical Presentation
Imaging
Pathology
Gross Examination
Histology
Final Diagnosis: Invasive Adenocarcinoma, Acinar Pattern Predominant, with Synchronous Foci of Atypical Adenomatous Hyperplasia (AAH)
Key Points for Differentiating AIS from AAH
What Is the Definition of AIS?
What Is the Definition of AAH?
What Is the Relationship Between AAH and AIS?
How Can Radiologic Features Help Distinguish AAH and AIS?
What Is the Difference in Prognosis Between AAH and AIS?
References
6: Invasive Adenocarcinoma Versus Adenocarcinoma In Situ
Case Presentation
Pathologic Diagnosis: Invasive Lung Adenocarcinoma, Acinar Predominant
What Are the Clinical and Prognostic features of Lung Adenocarcinoma?
What Are the Radiologic Features of Lung Adenocarcinoma?
What Are the Pathologic Features of Lung Adenocarcinoma?
How Are Special Stains and Immunohistochemistry Used in the Diagnosis of Lung Adenocarcinoma? How About Genetic/Molecular Findings?
What Are the Diagnostic Criteria for Adenocarcinoma In Situ (AIS), Minimally Invasive Adenocarcinoma (MIA), and Invasive Adenocarcinoma?
How Is “Invasion” Defined in Invasive Lung Adenocarcinoma?
What Is the Prognosis for Adenocarcinoma In Situ (AIS) and Minimally Invasive Adenocarcinoma (MIA) Versus Invasive Adenocarcinoma?
What Percentage of Resected Lung Adenocarcinomas Are Classified as Adenocarcinoma In Situ (AIS) and Minimally Invasive Adenocarcinoma (MIA) Versus Invasive Adenocarcinoma?
How Does Tumor Size Play a Role in the Staging of Lung Adenocarcinoma According to the Eighth Edition AJCC Staging Manual?
What Does Lepidic Pattern Look like? Where Does the Word “Lepidic” Come from?
How Are Acinar, Solid, Papillary, and Micropapillary Patterns of Lung Adenocarcinoma Defined?
How Does One Approach a Small Biopsy Specimen that Shows Only Non-mucinous adenocarcinoma with Lepidic Growth Pattern?
How Does One Approach a Case with Multiple Lepidic-Predominant Lesions, for Example, a Lobectomy Specimen with Multiple Discrete Foci of Lepidic-Prominent Adenocarcinoma, Minimally Invasive Adenocarcinoma, and Adenocarcinoma In Situ?
What Is the Differential Diagnosis for Lung Adenocarcinoma?
References
7: Solid Pulmonary Adenocarcinoma Versus Large-Cell Undifferentiated Carcinoma
Case Presentation
Final Diagnosis: Solid-Type Pulmonary Adenocarcinoma
What Are the Clinical and Prognostic Features of Solid-Type Pulmonary Adenocarcinoma (SPA), and How Do They Differ from Large-Cell Undifferentiated Carcinoma (LCUC)?
Can Radiologic Studies Be Used to Distinguish SPA from LCUC?
What Are the Pathologic Features of SPA and LCUC? How Can Special Stains Be Used to Distinguish These Two Entities?
Are Genetic/Molecular Findings Useful in the Diagnosis and Treatment of SPA and LCUC?
References
8: Large-Cell Neuroendocrine Carcinoma Versus Solid-Predominant Lung Adenocarcinoma
Case Presentation
Diagnosis: Large-Cell Neuroendocrine Carcinoma (LCNEC)
What Are the Key Clinicopathologic Findings of LCNEC and Solid Adenocarcinoma of the Lung?
Are There any Features on Radiologic Imaging that Would Help Diagnose and Differentiate LCNEC and Solid-Predominant Adenocarcinoma?
What Immunohistochemical Stains Are Helpful for Diagnosing and Differentiating These Two Entities, Particularly on Small Biopsy/Cytology Specimens?
Are There any Diagnostic Pitfalls with Immunohistochemistry to Be Aware of?
What Are Genetic Differences, and Is There any Impact on Therapy?
References
9: Poorly Differentiated Squamous Cell Carcinoma Versus Solid Pattern Adenocarcinoma
Case Presentation
Pathologic Diagnosis: Poorly Differentiated Squamous Cell Carcinoma
What Are the Histopathologic Features of Lung Adenocarcinoma and Squamous Cell Carcinoma?
What Are the Immunohistochemical Stains Often Utilized to Differentiate Poorly Differentiated Lung Squamous Cell Carcinoma from Solid Adenocarcinoma?
What Are the Differences in the Prognosis and Molecular Findings between Lung Squamous Cell Carcinoma and Adenocarcinoma?
References
10: Invasive Mucinous Adenocarcinoma Versus Ciliated Muconodular Papillary Tumor
Case Presentation
Final Diagnosis: Invasive Mucinous Adenocarcinoma (IMA) of the Lung
What Are the Clinical and Prognostic Features of IMA, and how Do they Differ from Ciliated Muconodular Papillary Tumor (CMPT)?
How Can Radiologic Studies Be Used to Distinguish IMA from CMPT?
What Are the Pathologic Features of IMA and CPMT? How Can Immunohistochemistry Be Used to Distinguish these Two Entities?
Are Genetic/Molecular Findings Different Between IMA and CMPT?
How to Differentiate IMA from Colloid Adenocarcinoma or Mucinous Adenocarcinoma Metastatic to the Lung?
How to Diagnose a Tumor with Mixed Morphologic Features of IMA and Invasive Nonmucinous Adenocarcinoma?
References
11: Mucoepidermoid Carcinoma Versus Adenosquamous Carcinoma
Case Presentation
Final Diagnosis: Mucoepidermoid Carcinoma, Low Grade
What Is Mucoepidermoid Carcinoma?
How Common Is Bronchopulmonary Mucoepidermoid Carcinoma?
How Do Patients with Bronchopulmonary Mucoepidermoid Carcinoma Present?
When Should I Consider Mucoepidermoid Carcinoma in the Differential Diagnosis?
What Ancillary Studies Are Helpful to Establish a Diagnosis of Mucoepidermoid Carcinoma?
How Are Bronchopulmonary Mucoepidermoid Carcinomas Graded?
How Do I Distinguish High-Grade Mucoepidermoid Carcinoma from Adenosquamous Carcinoma?
Do I Need to See Three Cell Populations to Suggest a Diagnosis of Mucoepidermoid Carcinoma?
References
12: Large-Cell (Undifferentiated) Carcinoma (LCC) Versus Large-Cell Neuroendocrine Carcinoma (LCNEC)
Case Presentation 1
Case Presentation 2
What Are the Diagnostic Definitions of LCC and LCNEC?
What Are the Clinical and Prognostic Features of LCC, and How Do they Differ from LCNEC?
How Has Molecular Genetics Played a Role in Defining LCNEC and LCC?
Summary
References
13: Large-Cell Neuroendocrine Carcinoma Versus Small-Cell Carcinoma of the Lung
Case Presentation
Final Pathologic Diagnosis: Large-Cell Neuroendocrine Carcinoma
How Do LCNEC Present Clinically? What Are the Imaging Findings?
What Are the Key Pathologic Features of LCNEC?
What Are the Molecular Features of LCNEC?
What Are the Key Points in Differentiating LCNEC from SCLC?
What Are the Clinical and Radiographic Characteristics that Distinguish LCNEC from SCLC?
What Are the Architectural Features that Suggest LCNEC over SCLC?
What Are the Cytologic Features that Suggest LCNEC over SCLC?
What Are the Immunohistochemical Differences Between LCNEC and SCLC?
References
14: Atypical Carcinoid Tumor Versus Large-Cell Neuroendocrine Carcinoma
Case Presentation
Final Pathologic Diagnosis: Atypical Carcinoid
What Is the Definition of Atypical Carcinoid?
What Are the Clinical Features of Atypical Carcinoid?
What Are the Radiographic Features of Atypical Carcinoid?
What Are the Pathologic Features of Atypical Carcinoid?
Is there a Precursor Lesion to Atypical Carcinoid?
What Are the Genetic and Molecular Alterations Seen in Atypical Carcinoid?
What Is the Differential Diagnosis for Atypical Carcinoid?
What Are the Pathologic Features to Differentiate Large-Cell Neuroendocrine Carcinomas from Atypical Carcinoid?
How Does Large-Cell Neuroendocrine Carcinoma Differ Clinically from Atypical Carcinoid?
References
15: Small-Cell Carcinoma Versus Atypical Carcinoid Tumor
Case Presentation
Pathologic Diagnosis: Small-Cell Carcinoma of the Lung (SCLC)
What Is the Definition of SCLC of the Lung?
What Are the Clinical and Prognostic Features of SCLC?
What Are the Typical Symptoms of Patients with SCLC?
What Are the Radiographic Features of SCLC?
What Are the Pathologic Features of SCLC?
What Are the Genetic and Molecular Alterations Seen in SCLC?
What Is the Differential Diagnosis of SCLC?
How Does One Differentiate SCLC from Atypical Carcinoid (AC)?
How Does AC Differ Clinically from SCLC?
References
16: Typical Versus Atypical Carcinoid and Diffuse Idiopathic Neuroendocrine Cell Hyperplasia Versus Carcinoid Tumorlets
Case Presentation
Final Pathologic Diagnosis: Typical Carcinoid
Where Are Pulmonary Neuroendocrine Cells Found, and What Is Neuroendocrine Hyperplasia?
What Is Pulmonary Carcinoid Tumor, and What Are its Clinical Features?
What Are the Characteristic Histopathologic and Immunohistochemical Features?
What Is an Atypical Carcinoid, and What Features Distinguish them from Typical Carcinoid?
Are there any Features Which Have Prognostic Significance?
How Do I Differentiate Pulmonary Carcinoid from Other Primary Pulmonary Malignancies?
How Is Primary Pulmonary Carcinoid Differentiated from Metastasis?
What Is DIPNECH, and how Is it Differentiated from NECH?
What Are Carcinoid Tumorlets, and how Are they Distinguished from NECH and DIPNECH?
References
17: Minute Meningothelial-Like Nodules Versus Tumorlet
Case Presentation
Pathologic Diagnosis: Minute Pulmonary Meningothelial-Like Nodules (MPMNs)
What Are MPMNs and its Main Differential on Microscopic Evaluation?
Are MPMNs Related to Central Nervous System Meningiomas and/or Primary Pulmonary Meningiomas?
What Immunohistochemical Findings Can Help Differentiate MPMNs from Pulmonary Tumorlets?
Why Is it Important for Pathologists to Be Aware of MPMNs and Pulmonary Tumorlets?
References
18: Primary Lung Versus Metastatic Adenocarcinoma
Case Presentation
Pathologic Diagnosis: Lung, Right Upper and Lower Lobes. Bilobectomy: Adenocarcinoma, Consistent with Metastasis from Ovarian Endometrioid Carcinoma
What Is the Clinical Relevance of Distinguishing Metastasis from Primary Lung Adenocarcinoma, and Will it Change Prognosis?
What Imaging Findings Are Helpful in Distinguishing Metastasis from Primary Lung Adenocarcinoma?
What Histopathologic Features Are Helpful in Distinguishing Metastasis from Primary Lung Adenocarcinoma, and how Is Immunohistochemistry Contributory?
References
19: Metastatic Urothelial Carcinoma Versus Squamous Cell Carcinoma
Case Presentation
Final Pathologic Diagnosis: Metastatic High-Grade Urothelial Carcinoma
What Are the Clinical, Radiologic, and Prognostic Features of Primary Squamous Cell Carcinoma of the Lung?
What Are the Clinical, Radiologic, and Prognostic Features of Metastatic Urothelial Carcinoma?
What Are the Gross Examination Features of Lung SCC?
What Are the Histologic Features of Lung SCC?
What Are the Gross Examination Features of Metastatic UC?
What Are the Histologic Features of Metastatic UC?
How Does One Differentiate Between Metastatic UC and SCC?
What Is the Prognosis of Metastatic Urothelial Cell Carcinoma and Primary Lung Squamous Cell Carcinoma?
References
20: Thymic Carcinoma Versus Lung Squamous Cell Carcinoma
Case Presentation
Final Diagnosis: Thymic Squamous Cell Carcinoma
Key Points for Differentiating Thymic Carcinoma Versus Lung Squamous Cell Carcinoma
How Do the Clinical Presentations of Patients with Thymic Carcinoma and Lung Squamous Cell Carcinoma Differ?
Are Imaging Features, Including Localization, Helpful in Determining the Origin of the Tumor?
Does Histology Alone Distinguish Between Thymic and Lung Squamous Cell Carcinoma?
Can Immunohistochemistry Distinguish Between Thymic and Lung SCC?
Does Molecular Testing Help to Distinguish Thymic Carcinoma and Lung SCC?
Squamous Cell Carcinoma Is Present in the Thymus. Could this Be a Metastasis of Primary Lung Squamous Cell Carcinoma?
Does the Presence of Extra-Thoracic Metastasis Favor SCC of Lung Origin?
Does Thymic SCC Arise from a Pre-existing Thymoma?
References
21: Pulmonary Epithelioid Hemangioendothelioma Versus Carcinoma and Other Epithelioid Neoplasms
Case Presentation
Final Diagnosis: Pulmonary Epithelioid Hemangioendothelioma
What Is the Definition of Epithelioid Hemangioendothelioma?
What Are the Epidemiologic Factors?
What Are the Clinical and Radiologic Considerations of Pulmonary Epithelioid Hemangioendothelioma?
What Are the Macroscopic Features of Epithelioid Hemangioendothelioma?
What Are the Histologic and Immunophenotypic Features of Epithelioid Hemangioendothelioma?
What Are the Genetics of Epithelioid Hemangioendothelioma?
What Is the Prognosis of Epithelioid Hemangioendothelioma?
What Are the Most Common Differential Diagnoses of Pulmonary Epithelioid Hemangioendothelioma?
References
22: Epithelioid Malignant Mesothelioma Versus Adenocarcinoma
Case Presentation
Pathologic Diagnosis: Epithelioid Malignant Mesothelioma
What Are the Panels of Mesothelial and Epithelial Markers to Separate Epithelioid Malignant Mesothelioma from Adenocarcinoma?
What Are the Pitfalls of the Various Mesothelial and Epithelial Markers Utilized to Distinguish Epithelioid Malignant Mesothelioma from Adenocarcinoma?
What Biomarkers Are Useful in Differentiating Malignant Mesothelioma from Reactive Mesothelial Cells?
Can We Reliably Distinguish Malignant Mesothelioma from Metastatic Adenocarcinoma on Imaging?
How Can Electron Microscopy Help in the Diagnosis of Malignant Mesothelioma?
References
23: Pleomorphic Carcinoma Versus Sarcomatoid Malignant Mesothelioma
Case Presentation
Final Pathologic Diagnosis: Pleomorphic (Spindle and Giant Cell) Carcinoma with Adenocarcinoma Component (pT3 N1)
What Is the Definition of Pleomorphic Carcinoma of the Lung?
What Are the Clinical, Radiographic, and Prognostic Features of Pleomorphic Carcinoma of the Lung?
What Are the Pathologic Features of Pleomorphic Carcinoma of the Lung?
Gross Examination
Histology
Immunohistochemistry
What Are the Genetic and/or Molecular Features of Pleomorphic Carcinoma of the Lung?
What Are the Differential Diagnoses for Pleomorphic Carcinoma of the Lung?
What Are the Clinicopathologic Features of Sarcomatoid Malignant Mesothelioma?
How Does One Differentiate Pleomorphic Carcinoma of the Lung from Sarcomatoid Malignant Mesothelioma?
Are There Any Molecular Markers that Can Help Differentiate Sarcomatoid Malignant Mesothelioma from Pleomorphic Carcinoma of the Lung?
References
24: Primary Sarcoma (Unclassified) Versus Sarcomatoid Mesothelioma/Carcinoma
Case Presentation
Final Pathologic Diagnosis: Primary Pulmonary Undifferentiated Pleomorphic Sarcoma (PPUPS)
What Are the Clinical Features of PPUPS, and How Do They Differ from Sarcomatoid Mesothelioma/Carcinoma?
What Are the Pathologic Features of PPUPS and Sarcomatoid Mesothelioma/Carcinoma?
Gross
Histology
How Can Ancillary Tests Be Used to Distinguish UPS Versus Sarcomatoid Mesothelioma/Carcinoma?
Immunohistochemistry
Molecular Testing
What Is the Most Specific Test for Diagnosing PPUPS?
What Are the Helpful Immunohistochemical Stains Used in Diagnosing Sarcomatoid Mesothelioma?
What Are the Helpful Immunohistochemical Stains Used in Diagnosing Sarcomatoid Carcinoma?
What Is the Next Step if You Find a True UPS in the Lung?
References
25: Synovial Sarcoma Versus Solitary Fibrous Tumor
Case Presentation
Final Diagnosis: Synovial Sarcoma
What Are the Clinical and Prognostic Features of SS, and How Do They Differ from SFT?
What Are the Pathologic Features of SS? How Do They Differ from SFT?
How Can Immunohistochemistry and Molecular Testing Be Used to Distinguish SS from SFT?
References
26: Inflammatory Myofibroblastic Tumor Versus Organizing Pneumonia
Case Presentation
Diagnosis: Inflammatory Myofibroblastic Tumor
What Is the Definition, Epidemiology, and Clinical Presentation of Inflammatory Myofibroblastic Tumor (IMT), and How Does It Differ from Organizing Pneumonia (OP)?
Do IMT and OP Look Differently on Radiographic Imaging?
What Are the Pathological Features of IMT and OP? What Are the Similarities and Differences? Can Immunohistochemical Studies Help in Differentiating These Two?
What Are the Genetic/Molecular Findings of IMT?
What Are the Treatment Modalities for Pulmonary IMTs, and What Is the Prognosis?
References
27: Metastatic Malignant Epithelioid Melanoma Versus Poorly Differentiated Carcinoma
Case Presentation
Final Diagnosis: Metastatic Melanoma
What Are the Clinical Presentations of Pulmonary Metastatic Melanoma, and How Do They Differ from Primary Carcinoma?
What Are the Pathologic Features of Metastatic Melanoma and Poorly Differentiated Carcinoma? How Can Immunohistochemistry and Molecular Testing Be Used to Distinguish These Two Entities?
Key Points for Differentiating Epithelioid Metastatic Melanoma from Poorly Differentiated Primary Carcinoma
References
28: Pulmonary Epithelioid Angiosarcoma Versus Carcinoma
Case Presentation
Pathologic Diagnosis: Epithelioid Angiosarcoma
What Is Epithelioid Angiosarcoma? What Are the Clinical, Demographic, Treatment, and Prognostic Features?
What Are the Radiologic Features of Primary Pulmonary Angiosarcoma?
What Are the Histologic and Immunophenotypic Features of Epithelioid Angiosarcoma?
Does Angiosarcoma Have Any Recurrent Molecular Abnormalities?
What Is the Differential Diagnosis of Pulmonary Epithelioid Angiosarcoma?
References
29: Epithelioid Sarcoma Versus Large-Cell (Undifferentiated) Carcinoma
Case Presentation
Final Pathologic Diagnosis: Metastatic Epithelioid Sarcoma
What Are the Clinical Features of Epithelioid Sarcoma, and How Do They Differ from Large-Cell (Undifferentiated) Carcinoma?
What Are the Pathologic Features of Epithelioid Sarcoma and Large-Cell (Undifferentiated) Carcinoma?
Gross
Histology
How Can Ancillary Tests Be Used to Distinguish Epithelioid Sarcoma Versus Large-Cell (Undifferentiated) Carcinoma?
Immunohistochemistry
Molecular Testing
What Is the Most Specific Test for Diagnosing Epithelioid Sarcomas?
What Is the Most Specific Test for Diagnosing Large-Cell (Undifferentiated) Carcinoma?
What Is the Best Approach If You Find a Lung Tumor with Atypical Large Epithelioid Cytology?
References
30: Intimal Sarcoma Versus Other Spindle Cell Neoplasms
Case Presentation
Pathologic Diagnosis: Intimal Sarcoma
What Is the Definition of Intimal Sarcoma?
What Are the Epidemiologic Factors?
What Are the Clinical Considerations of Intimal Sarcoma?
What Are the Gross Macroscopic Features of Intimal Sarcoma?
What Are the Histologic and Immunophenotypic Features of Intimal Sarcoma?
What Are the Genetics of Intimal Sarcoma?
How Are Most Cases of Intimal Sarcoma Treated?
What Is the Prognosis of Intimal Sarcoma?
What Are the Most Common Differential Diagnoses of Intimal Sarcoma?
References
31: Sclerosing Pneumocytoma Versus Lung Adenocarcinoma
Case Presentation
Final Pathologic Diagnosis: Sclerosing Pneumocytoma
What Is the Histogenesis and Epidemiology of Sclerosing Pneumocytomas?
What Are the Differential Diagnoses for Sclerosing Pneumocytoma?
How Do Sclerosing Pneumocytoma and Lung Adenocarcinoma Differ on Imaging?
How Do Sclerosing Pneumocytoma and Lung Adenocarcinoma Differ Grossly?
How Do Sclerosing Pneumocytoma and Lung Adenocarcinoma Differ Histologically and Immunohistochemically?
How Does One Differentiate Between Sclerosing Pneumocytoma and Lung Adenocarcinoma on Cytologic Specimens or Intraoperative Frozen Sections?
How Do Sclerosing Pneumocytoma and Lung Adenocarcinoma Differ at the Molecular Level?
References
32: Erdheim-Chester Disease Versus Reactive Inflammatory Infiltrates
Case Presentation
Pathologic Diagnosis: Erdheim-Chester Disease
What Are Classic Clinical Features of Erdheim-Chester Disease?
What Are the Radiographic Findings of Erdheim-Chester Disease? Can Imaging Help Distinguish Pulmonary Involvement by Erdheim-Chester from Other Interstitial Lung Disease Processes?
What Are the Major Histopathologic Features of Erdheim-Chester Disease and How Do They Differ from a Reactive Inflammatory Process?
How Helpful Is Molecular Testing When Considering a Diagnosis of Erdheim-Chester Disease?
References
33: Mucosal Marginal Zone Lymphoma Versus Follicular Bronchiolitis
Case Presentation
Pathologic Diagnosis: Pulmonary Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT Lymphoma)
What Is the Definition of a MALT Lymphoma? What Are Its Clinical and Prognostic Features?
What Are the Histologic and Immunophenotypic Features of MALT Lymphomas?
What Is the Differential Diagnosis for MALT Lymphomas?
What Is the Definition of Follicular Bronchiolitis (FB)? What Are Its Clinical and Prognostic Features?
What Are the Histologic Features of Follicular Bronchiolitis?
What Are the Radiographic Features of MALT Lymphomas and Follicular Bronchiolitis?
How Does One Differentiate a MALT Lymphoma from Follicular Bronchiolitis?
References
34: Primary Pulmonary Diffuse Large B-Cell Lymphoma Versus Poorly Differentiated Carcinomas
Case Presentation
Pathologic Diagnosis: Primary Pulmonary Diffuse Large B-Cell Lymphoma, Not Otherwise Specified, Non-Germinal Center (Or Activated) B-Cell Subtype, with Double-Expressor Phenotype
What Is the Definition of a Primary Pulmonary Diffuse Large B-Cell Lymphoma (PPDLBCL)?
What Are the Clinical, Radiographic, and Prognostic Features and Treatment of PPDLBCL?
What Are the Pathologic Features of PPDLBCL?
What Are the Differential Diagnoses of PPDLBCL?
Poorly Differentiated Squamous Cell Carcinoma and Adenocarcinoma
Large Cell Undifferentiated Carcinoma
Small Cell Carcinoma (SCLC) and Large Cell Neuroendocrine Carcinoma (LCNEC)
Pulmonary Lymphoepithelioma-Like Carcinoma and Metastatic Undifferentiated Carcinoma of the Nasopharynx
Metastatic Melanoma
References
35: Lymphomatoid Granulomatosis Versus Granulomatosis with Polyangiitis
Case Presentation
Pathologic Diagnosis: Lymphomatoid Granulomatosis, Grade 2 of 3
What Is the Definition of a Lymphomatoid Granulomatosis?
What Are the Clinical, Radiographic, and Prognostic Features of Pulmonary Lymphomatoid Granulomatosis?
What Are the Pathologic Features of Pulmonary Lymphomatoid Granulomatosis?
What Are the Main Differential Diagnoses of Pulmonary Lymphomatoid Granulomatosis?
How Does One Differentiate Pulmonary Lymphomatoid Granulomatosis from Granulomatosis with Polyangiitis?
References
36: Primary Pulmonary Classic Hodgkin Lymphoma Versus Other Non-Hodgkin Lymphomas
Case Presentation
Pathologic Diagnosis: Pulmonary Classic Hodgkin Lymphoma, Probably Primary
What Is the Definition of a Primary Pulmonary Classic Hodgkin Lymphoma (PPCHL)?
What Are the Clinical, Radiographic, and Prognostic Features and Treatment of PPCHL?
What Are the Pathologic Features of PPCHL?
What Are the Differential Diagnoses for PPCHL?
T-Cell/Histiocyte-Rich Large B-Cell Lymphoma (THRLBCL)
Anaplastic Large Cell Lymphoma (ALCL)
Peripheral T-Cell Lymphoma, Not Otherwise Specified (PTCL)
EBV+ Diffuse Large B-Cell Lymphoma (EBV+ DLBCL), NOS
Pulmonary Lymphomatoid Granulomatosis (PLG)
References
37: Posttransplant Lymphoproliferative Disorders in Lung After Lung Transplantation Versus Infection and Inflammation
Case Presentation
Pathologic Diagnosis: EBV-Positive, Polymorphic Posttransplant Lymphoproliferative Disorder (PTLD) in the Lung After Transplantation
What Is the Definition of PTLD?
What Are the Clinical, Radiographic, Prognostic Features, and Treatment of PTLDs in the Lung After Lung Transplantation?
What Are the Pathologic Features of PTLDs in the Lung After Lung Transplantation?
Nondestructive PTLDs
Polymorphic PTLDs (P-PTLDs)
Monomorphic PTLDs (M-PTLDs
Classic Hodgkin Lymphoma (CHL) PTLDs
What Are the Differential Diagnoses for PTLDs in the Lung After Lung Transplantation?
References
Part II: Non-neoplastic Lung Pathology
38: Usual Interstitial Pneumonia Versus Nonspecific Interstitial Pneumonia
Case Presentation
Final Pathological Diagnosis: Usual Interstitial Fibrosis (UIP)
What Are the Clinical Signs and Symptoms of NSIP and UIP?
What Is the Clinical Course of These Diseases?
What Changes Can be Seen on Chest Radiographs in UIP and NSIP?
What Changes Can be Seen on Chest HRCT in UIP and NSIP?
What Are Features of UIP and NSIP on Gross Examination of Surgical Specimens?
What Are the Histologic Features of the UIP Pattern?
What Are the Histologic Features of NSIP?
References
39: Hypersensitivity Pneumonitis Versus Usual Interstitial Pneumonia
Case Presentation
Pathologic Diagnosis: Chronic Hypersensitivity Pneumonitis
What Are some of the Differences in the Clinical Presentation of Patients with Hypersensitivity Pneumonitis (HP) Versus Usual Interstitial Pneumonia (UIP)?
How Do HP and UIP Differ on Radiographic Studies?
What Are the Gross Pathologic Differences Between UIP and HP?
How Can HP and UIP be Distinguished Histologically?
Are There Any Laboratory Tests That Can Aid in the Diagnosis of UIP or HP?
References
40: Organizing Pneumonia Versus Usual Interstitial Pneumonia
Case Presentation
Final Pathologic Diagnosis: Organizing Pneumonia
What Are the Clinical and Prognostic Characteristics of Cryptogenic Organizing Pneumonia and How Do They Differ from Idiopathic Pulmonary Fibrosis?
What Are the Radiologic Features of Organizing Pneumonia and How Do They Differ from Usual Interstitial Pneumonia?
What Histologic Features Can Be Used to Distinguish Organizing Pneumonia from Usual Interstitial Pneumonia?
References
41: Diffuse Alveolar Damage (Organizing Phase) Versus Nonspecific Interstitial Pneumonia
Case Presentation
Pathologic Diagnosis: Acute and Organizing Phases of Diffuse Alveolar Damage
What Is Diffuse Alveolar Damage?
What Are the Phases of DAD?
What Is Nonspecific Interstitial Pneumonia?
How Do DAD and NSIP Overlap Histologically?
How Can the Clinical History Help Distinguish DAD from NSIP?
Can Radiographic Findings Help Distinguish DAD from NSIP?
Are There Any Ancillary Studies That Can Be Used to Distinguish DAD from NSIP?
References
42: Chronic Eosinophilic Pneumonia Versus Organizing Pneumonia
Case Presentation
Pathologic Diagnosis: Consistent with Chronic Eosinophilic Pneumonia
What Is the Definition of Chronic Eosinophilic Pneumonia and Organizing Pneumonia? What Are Their Clinical and Prognostic Features?
What Are the Radiographic Features of Chronic Eosinophilic Pneumonia?
What Are the Pathogenesis and Pathologic Features of Chronic Eosinophilic Pneumonia, and How Does That Differ from Organizing Pneumonia?
What Are Other Differential Diagnoses for Chronic Eosinophilic Pneumonia?
References
43: Pulmonary Langerhans Cell Histiocytosis with Fibrosis Versus Organizing Pneumonia
Case Presentation
Pathologic Diagnosis: Pulmonary Langerhans Cell Histiocytosis
What Is Pulmonary Langerhans Cell Histiocytosis?
What Are the Typical Imaging Findings of Pulmonary Langerhans Cell Histiocytosis?
What Are the Pathologic Features of Pulmonary Langerhans Cell Histiocytosis?
What Is the Differential Diagnosis of Pulmonary Langerhans Cell Histiocytosis?
What Is Organizing Pneumonia?
What Differentiates Pulmonary Langerhans Cell Histiocytosis from Organizing Pneumonia Clinically?
What Differentiates Pulmonary Langerhans Cell Histiocytosis from Organizing Pneumonia on Imaging?
What Differentiates Pulmonary Langerhans Cell Histiocytosis from Organizing Pneumonia on Histopathology?
References
44: IgG4-Related Lung Disease Versus Other Fibroinflammatory Processes
Case Presentation
Final Diagnosis: Pulmonary IgG4-Related Disease
What Are the Histologic and Immunohistochemical Criteria for Diagnosing IgG4-Related Lung Disease?
Can a Definitive Diagnosis of IgG4-Related Disease Be Given Based on Histopathology and Immunohistochemistry Alone?
How Do We Know If a Resection Specimen Meets “Highly Histologically Suggestive” or “Probable Histologic Features” Criteria?
How Do We Determine the IgG4 Plasma Cell Ratio?
What Else Should We Include in the Differential When Considering a Diagnosis of IgG4-Related Lung Disease?
Are Clinical and Imaging Findings Helpful to Distinguish IgG4-Related Disease from Other Fibroinflammatory Conditions Such as IMT and NSCHL?
What Are the Main Histologic Differences Between IgG4-Related Disease, IMT, and Pulmonary NSCHL?
How Do We Distinguish IgG4-Related Disease from an Organizing Abscess?
What Is the Difference Between IgG4-Related Disease and Plasma Cell Granuloma?
How Do We Distinguish IgG4-Related Disease from Pulmonary Langerhans Cell Histiocytosis?
Is Elevated Serum IgG4 a Necessary Criterion for IgG4-Related Disease?
Are Distinct or Distant Foci of IgG4+ Plasma Cells and Obliterative Vasculitis Supportive of a Diagnosis of IgG4-Related Disease?
Is the Vasculitis Found in IgG4-Related Disease Necrotizing or Non-necrotizing?
Can IgG4-Related Disease Affect the Pleura?
References
45: Pulmonary Alveolar Proteinosis Versus Pulmonary Edema
Case Presentation
Pathologic Diagnosis: Pulmonary Alveolar Proteinosis (PAP)
How Does the Demographics and Clinical Symptoms Differ Between PAP and Pulmonary Edema?
Can PAP Be Distinguished from Pulmonary Edema Through Radiologic Studies?
What Cytological and Histological Findings Are Indicative of a Diagnosis of PAP?
Can Any Laboratory Tests Outside of Tissue Biopsy Be Useful in Establishing a Diagnosis of PAP?
What Are the Causes of PAP, and How Is It Treated?
Are Patients with PAP More Prone to Any Specific Secondary Infections?
What Is the Prognosis for Patients with PAP?
References
46: Nonspecific Interstitial Pneumonia Versus Lymphoid Interstitial Pneumonia Versus Follicular Bronchiolitis
Clinical Presentation and Imaging
The Final Pathologic Diagnosis Rendered: Nonspecific Interstitial Pneumonia, Cellular Pattern
What Is the Differential Diagnosis of Interstitial Lymphoid Infiltrates in the Lung?
What Is NSIP?
What Is the Typical Clinical Presentation for NSIP?
What Is the Typical Clinical Presentation of LIP?
What Is FB and How Does It Typically Present Clinically?
What Are Radiographic Findings That Support a Diagnosis of NSIP?
What Are Radiographic Findings That Support a Diagnosis of LIP or FB?
Are Gross Pathology Findings Useful in Distinguishing NSIP, LIP, and FB?
What Are the Histologic Features of NSIP? What Histologic Subtypes/Patterns of NSIP Are Important in the Context of This Patient?
What Are the Histologic Features of LIP?
How Do the Histologic Features of NSIP and LIP Overlap?
What Are the Histologic Features of FB?
Do the Histologic Features of NSIP and FB Overlap?
What Are the Recommended Ancillary Studies Needed for This Case?
What Are Key Features That Can Distinguish NSIP from LIP and FB?
What Is the Prognosis for NSIP? How Does This Differ from LIP and FB?
References
47: Respiratory Bronchiolitis Versus Desquamative Interstitial Pneumonia
Clinical Presentation and Imaging
The Final Pathologic Diagnosis Rendered: Desquamative Interstitial Pneumonia
What Is Desquamative Interstitial Pneumonia and How Does It Relate to Respiratory Bronchiolitis?
What Is the Typical Clinical Presentation for RB?
What Is the Distinction Between RB and RB-ILD? What Is the Typical Clinical Presentation of RB-ILD?
What Are the Typical Radiographic Findings in RB-ILD?
What Is the Typical Clinical Presentation of DIP?
What Are the Typical Radiographic Findings in DIP?
What Are the Histologic Features of RB/RB-ILD?
What Are the Histologic Features of DIP?
How Are DIP and RB/RB-ILD Distinguished Radiographically?
How Are DIP and RB/RB-ILD Distinguished Histologically?
Can the Diagnoses of RB-ILD and/or DIP Be Made on a Small Biopsy?
What Is the Prognosis for RB, RB-ILD, and DIP?
What Other Diagnoses Can Be Considered in This Case?
What Ancillary Studies Can Be Used in the Pathologic Workup of This Patient?
References
48: Constrictive Bronchiolitis
Clinical History
Pathologic Findings
Diagnosis: Constrictive Bronchiolitis (CB)
What Are the Etiologies and Clinical Presentations of Constrictive Bronchiolitis?
What Are the Histologic Features of Constrictive Bronchiolitis? What Are the Key Features to Differentiate Constrictive Bronchiolitis from Normal Lung?
What Are the Key Features to Differentiate Constrictive Bronchiolitis from Organizing Pneumonia?
What Are the Treatment Options and Prognosis of Constrictive Bronchiolitis?
References
49: Granulomatosis with Polyangiitis Versus Mycobacterial/Fungal Infection
Case Presentation
Pathologic Diagnosis: Granulomatosis with Polyangiitis (GPA)
Discussion Questions
What Is GPA?
How Does a Patient with GPA Present Clinically?
What Are the Diagnostic Features of GPA?
What Are the Imaging Findings of GPA and Mycobacterial/Fungal Infection?
What Are the Gross Findings in GPA?
What Are the Histopathologic Findings in GPA?
How Does GPA Differ Histologically from Pulmonary Infections Such as Mycobacterial or Fungal Infection?
References
50: Eosinophilic Granulomatosis with Polyangiitis Versus Eosinophilic Pneumonia
Case Presentation
Pathologic Diagnosis
Discussion Questions
What Is Eosinophilic Pneumonia?
What Is the Differential Diagnosis of Eosinophilic Pneumonia?
What Is Meant by Acute and Chronic Eosinophilic Pneumonia?
What Is Eosinophilic Granulomatosis with Polyangiitis (EGPA)?
What Are the Clinical Features of EGPA?
What Laboratory Findings Support the Diagnosis of EGPA?
How Does EGPA Affect the Lung?
What Are the Histopathologic Findings in EGPA?
How Is EGPA Histologically Distinguished from Acute (AEP) and Chronic (CEP) Eosinophilic Pneumonia?
What Are the Radiographic Findings in EGPA and How Do They Differ from Acute and Chronic Eosinophilic Pneumonia?
How Does EGPA Differ from GPA?
References
51: Pulmonary Sarcoidosis Versus Mycobacterial/Fungal Disease in the Lung
Case Presentation
Final Diagnosis: Non-necrotizing Granulomas, Consistent with Sarcoidosis, in a Background of Acute Fibrinous and Organizing Pneumonitis
Clinical Considerations
Radiologic Features
Histologic Features
Special Stains and Microbiologic Features
Key Points for Distinguishing Sarcoidosis from Mycobacterial and Other Infections
What Are Three Key Histopathologic Features That Favor a Diagnosis of Sarcoidosis Over Mycobacterial Infection? Are These Findings Specific?
Other than Mycobacterium tuberculosis, What Infections Should Be Considered in a Patient with Granulomatous Pulmonary Inflammation?
Other than Infections, What Other Diseases Should Be Considered in a Patient with Granulomatous Pulmonary Inflammation?
References
52: Histoplasmosis, Blastomycosis, Coccidioidomycosis, and Cryptococcosis in the Lung
Case Presentation
Final Pathologic Diagnosis: Coccidioidomycosis of the Lung
Clinical Considerations
Radiologic Features
Histologic and Immunophenotypic Features
Molecular Testing
Key Points for Differentiating Coccidioides, Cryptococcus, Blastomyces, and Histoplasma
Each of These Pathogens Has Yeast or Yeast-Like Forms in Tissue: What Morphologic Features Distinguish Them?
What Are Important Pitfalls in the Identification of These Organisms?
What Additional Diagnostic Testing Is Important/Should Be Recommended?
References
53: Pneumocystis jirovecii Pneumonia Versus Histoplasmosis
Case Presentation
Final Diagnosis: Small Yeasts with Narrow-Based Budding
Clinical Considerations
Radiologic Features
Histologic Features
Special Stains
Molecular and Microbiologic Features
Key Points for Differentiating P. jirovecii and H. capsulatum
Both Pneumocystis jirovecii and Histoplasma capsulatum Cause Pulmonary Infections in Overlapping Patient Populations. What Histopathologic Features Help Distinguish Between P. jirovecii and H. capsulatum?
What Morphologic Features Help Distinguish These Two Organisms from Each Other?
What Laboratory Tests Are Available to Confirm the Diagnosis?
References
54: The Differential Diagnosis of Invasive Mold Infections in the Lung
Case Presentation
Final Diagnosis
Clinical Considerations
Radiologic Features
Histologic Features
Immunophenotypic Features
Special Stains
Molecular Features
Key Points for Differentiating Zygomycosis from Hyalohyphomycosis
What Are the Key Morphologic Features that Distinguish Zygomycetes (Mucorales) from Molds Like Aspergillus spp.?
What Are Important Pitfalls in Distinguishing Zygomycetes (Mucorales) from Molds Like Aspergillus spp.?
How Reliable Is the Identification of Fungal Hyphae in Tissue?
What Is the Role of Frozen Section in Evaluating for Invasive Fungal Disease?
What Are the Next Steps Beyond Histology for the Characterization of Molds?
References
55: Primary Pulmonary Arterial Hypertension Versus Secondary Pulmonary Hypertension
Case Presentation
Pathologic Diagnosis: Idiopathic Pulmonary Arterial Hypertension
What Is Pulmonary Hypertension?
Which Etiologies Are Associated with Pulmonary Hypertension?
What Do We Understand About the Causes of Primary Pulmonary Arterial Hypertension?
How Can Radiologic Studies Be Used to Diagnose and Classify Pulmonary Hypertension?
Can Histologic Findings Help Distinguish Between Primary and Secondary Pulmonary Hypertension?
References
56: Pulmonary Capillary Hemangiomatosis Versus Congestion
Case Presentation
Pathologic Diagnosis: Pulmonary Capillary Hemangiomatosis
What Is Pulmonary Capillary Hemangiomatosis?
Are There Imaging Features Specific for PCH?
How Can PCH be Histologically Distinguished from Vascular Congestion?
Are Genetic/Molecular Findings Useful in the Diagnosis and Treatment of PCH?
What Are the Treatment Modalities Available for PCH?
References
57: Pulmonary Veno-Occlusive Disease Versus Pulmonary Arterial Hypertension
Case Presentation
Diagnosis: Pulmonary Veno-Occlusive Disease (PVOD)
What Is the Definition and Epidemiology of Pulmonary Veno-Occlusive Disease (PVOD) and How Do They Differ from Pulmonary Arterial Hypertension (PAH)?
What Is the Etiology and Clinical Presentation of PVOD and How Do They Differ from PAH?
Do PVOD and PAH Look Differently on Radiographic Imaging?
What Are the Pathological Features of PVOD and PAH? What Are the Similarities and Differences?
What Are the Genetic/Molecular Findings of PVOD and How Is It Different from Those Seen in PAH?
What Are the Treatment Modalities and Prognosis for PVOD and PAH?
References
58: Lymphangioleiomyomatosis Versus Benign Metastasizing Leiomyoma
Case Presentation
Pathologic Diagnosis: Lymphangioleiomyomatosis
What Are the Clinical and Prognostic Features of LAM and How Do They Differ from Benign Metastasizing Leiomyoma (BML)?
How Can Radiologic Studies be Used to Distinguish LAM from BML?
What Are the Pathologic Features of LAM and BML? How Can Immunohistochemistry be Used to Distinguish These Two Entities?
Are Genetic/Molecular Findings Useful in the Diagnosis and Treatment of LAM?
Are BML Genetically Similar to Their Uterine Counterparts? Are These Truly Metastatic?
References
59: Diffuse Pulmonary Lymphangiomatosis Versus Lymphangioleiomyomatosis
Case Presentation
Final Diagnosis: Diffuse Pulmonary Lymphangiomatosis
What Are the Clinical Features of Diffuse Pulmonary Lymphangiomatosis (DPL) and How Do They Differ from Lymphangioleiomyomatosis (LAM)?
How Can Radiologic Studies be Used to Distinguish DPL from LAM?
What Are the Pathologic Features of DPL and LAM? How Can Immunohistochemistry be Used to Distinguish These Two Entities?
What Other Lesions Should I Consider in the Differential Diagnosis of DPL?
References
60: Intralobar Versus Extralobar Pulmonary Sequestration
Case Presentation
Pathologic Diagnosis: Intralobar Pulmonary Sequestration
What Is Pulmonary Sequestration?
How Do the Clinical Findings of Intralobar and Extralobar Pulmonary Sequestration Differ?
How Do the Radiologic Findings of Intralobar and Extralobar Pulmonary Sequestration Differ?
What Are the Histologic Findings of Pulmonary Sequestration?
References
Index