The Yokohama System for Reporting Endometrial Cytology: Definitions, Criteria, and Explanatory Notes

Foreword
Foreword
Preface
Preface: The Quest to Develop a Standardized Terminology for Endometrial Cytology
References
Introduction
Reference
Contents
Contributors
1: Endometrial Cytology in Historical Perspective
1.1 General Concepts
1.2 Dawning of the Endometrial Cytology
1.3 Endometrial Cytology Based on Cyto-Architecture of Tissue Fragments
1.4 Endometrial Sampling by Cervical Cytology
1.5 Development and Evaluation of Endometrial Cell Sampling Device
1.6 Endometrial Cytopathology and Cell Block Preparation
1.7 Endometrial Cytology by Means of Liquid-Based Cytology and Its Reporting System
1.8 Molecular-Based Approach with LBC Samples
References
2: Overview of the Yokohama System for Reporting Endometrial Cytology
2.1 Background
2.2 The Reproducibility Assessment of the Yokohama System
2.3 Clinical Handling in the Yokohama System for Reporting Endometrial Cytology
References
3: Pathogenetic Bases of the Yokohama System for Reporting Endometrial Cytology
References
4: Endometrial Cell Sampling Procedure to Obtain Cytologic Specimens
4.1 Significance of Endometrial Cytology for Women with Abnormal Uterine Bleeding at the Outpatient Clinic
4.2 Indications for the Use of Directly Sampled Endometrial Cytology (Table 4.1)
4.3 Collection Instruments and Evaluation of Endometrial Lesions by Endometrial Cytology
4.4 Techniques of Endometrial Sampling and Processing
4.5 Benefits and Harm of Directly Sampled Endometrial Cytology
References
5: Algorithmic Interpretational and Diagnostic Approach to Endometrial Cytology for the Yokohama System
5.1 Definition and Criteria
5.1.1 Inadequate Sample for Evaluation (TYS 0)
5.1.2 Negative for Malignant Tumors and Precursors (TYS1)
5.1.3 Atypical Endometrial Cells, Cannot Exclude EAH/EIN or Malignant Condition (ATEC-AE) (TYS4)
5.1.4 Malignant Neoplasms (Endometrial Carcinomas) (TYS6) or Endometrial Atypical Hyperplasia/Endometrioid Intraepithelial Neoplasia (EAH/EIN) (TYS5)
5.1.5 Endometrial Hyperplasia Without Atypia (TYS3)
5.1.6 Atypical Endometrial Cells of Undetermined Significance (ATEC-US) (TYS2)
5.2 Management
5.2.1 The Evaluation of the Reproducibility of the Cytological Diagnosis of Endometrial Lesions by the TYS
References
6: Evaluation of Sample Adequacy: Cytologic Criteria
6.1 Background
6.2 Definition
6.3 Explanatory Note
Reference
7: Processing Methodology of Endometrial Cytology Samples
7.1 Background
7.1.1 Processing Methodology of Endometrial Conventional Cytology Samples
7.1.2 Processing Methodology of Endometrial Liquid-Based Cytology (LBC) Samples
References
8: Negative for Malignant Tumors and Precursors: TYS1
8.1 Normal Endometrium [1]
8.2 Proliferative Endometrium (PE) [1]
8.2.1 Background
8.2.2 Definition
8.2.3 Criteria
8.3 Secretory Endometrium (SE) [1]
8.3.1 Background
8.3.2 Definition
8.3.3 Criteria
8.4 Menstrual Endometrium [1]
8.4.1 Background
8.4.2 Definition
8.4.3 Criteria
8.4.4 Differential Diagnosis
8.5 Atrophic Endometrium [1]
8.5.1 Background
8.5.2 Definition
8.5.3 Criteria
8.6 Benign Reactive Changes: IUD (Intrauterine Contraceptive Devices)
8.6.1 Background
8.6.2 Mechanism of Action of IUD
8.6.3 Occurrence of IUD Associated Cellular Change
8.7 Benign Reactive Change: MPA (Medroxyprogesterone Acetate)
8.7.1 Background
8.7.2 Adaptation Criteria of Fertility-Sparing Treatment [29]
8.7.3 Physiopathological Changes and Effects of MPA Therapy
8.7.4 Assessing the Efficacy of MPA Therapy: Cytological Criteria
8.8 Benign Reactive Changes: TAM(Tamoxifen)
8.8.1 Background
8.8.2 Cytological Findings in Endometrial Mucosa after TAM Therapy
8.8.3 Cytological Endometrial Findings after TAM Therapy
8.9 Arias-Stella Reaction (ASR)
8.9.1 Background
8.9.2 Cellular Changes of Arias-Stella Reaction (ASR)
References
9: Endometrial Hyperplasia without Atypia
9.1 Background
9.2 Definition
9.3 Diagnostic Criteria [7–12] (Figs. 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8 and 9.9)
9.4 Explanatory Note
References
10: Endometrial Atypical Hyperplasia/Endometrioid Intraepithelial Neoplasia
10.1 Background
10.2 Definition
10.3 Cytological Diagnostic Criteria [14–18] (Figs. 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 10.10, 10.11, 10.12 and 10.13)
10.4 Explanatory Note
References
11: Malignant Neoplasm
11.1 Endometrial Endometrioid Carcinoma
11.1.1 Background
11.1.2 Definition
11.1.3 Cytologic Diagnostic Criteria [6–10] (Figs. 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8 and 11.9)
11.1.4 Explanatory Note
11.2 Serous Carcinoma, Including Serous Endometrial Intraepithelial Carcinoma (SEIC)
11.2.1 Background
11.2.2 Definition
11.2.3 Cytologic Diagnostic Criteria (Figs. 11.21, 11.22, 11.23, 11.24, 11.25, 11.26 and 11.27)
11.2.4 Explanatory Note
11.3 Clear Cell Carcinoma
11.3.1 Background
11.3.2 Definition
11.3.3 Cytologic Diagnostic Criteria (Figs. 11.37, 11.38, 11.39, 11.40 and 11.41)
11.3.4 Explanatory Note
References
12: Endometrial Glandular and Stromal Breakdown (EGBD) as Benign Mimics of Malignancy
12.1 Background
12.2 Definition
12.2.1 Condensed Stromal Clusters (CSC)
12.2.2 Metaplastic Clusters with Irregular Protrusion (MCIP)
12.2.3 Light Green Body (LGB)
12.3 Criteria
12.3.1 Condensed Stromal Clusters (CSC)
12.3.2 Metaplastic Clusters with Irregular Protrusion (MCIP)
12.3.3 MCIP with Condensed Stromal Clusters (CSC)
12.3.4 Light Green Body (LGB)
12.4 How to Classify EGBD in the “Algorithmic Approach to the Yokohama System (TYS)”
12.5 Differential Diagnosis
12.5.1 Nuclear Findings in LBC: Discrimination Between EGBD and G1-EEC
12.5.2 Immunocytochemical Findings in LBC: Discrimination Between EGBD and EEC
12.5.2.1 CSC of EGBD versus CCC of EEC
12.5.2.2 SPSC (MCIP) of EGBD versus CCC of EEC/ESC
12.6 Explanatory Note
12.6.1 *1: Light Green Body (LGB)
12.6.2 *2: Comparison of the Frequency of Nuclear Shape
12.6.3 *3: IMP3 Immunocytochemical Expression in LBC Samples
References
13: Atypical Endometrial Cells (ATEC)
13.1 Background
13.2 Definition
13.3 ATEC-US
13.4 ATEC-AE
References
14: Cell Block Techniques for Endometrial Cytology Technical Procedures, Role of Immunocytochemistry, Advantages, Applications
14.1 Cell Block Preparation and Techniques
14.1.1 Cell Block Preparation
14.1.2 Cell Block Techniques
14.2 Immunocytochemistry
14.2.1 Application of Immunocytochemistry in Endometrial Cancer
14.2.1.1 Beta-Catenin
14.2.2 Distinguishing Endometrioid Carcinoma from Endocervical Carcinoma
14.2.2.1 NON-HPV-Related Carcinomas.
14.2.3 Distinguishing Endometrial Carcinoma from Colonic Adenocarcinoma
14.2.4 Distinguishing Endometrial Carcinoma from Ovarian Carcinoma
References
15: Molecular Pathology of Endometrial Carcinoma: A General Appraisal
15.1 Introduction
15.1.1 Molecular Alterations in Endometrioid Carcinoma
15.2 Molecular Alterations in Non-endometrioid Carcinomas
15.3 New Perspectives after TCGA Classification
15.4 Technical Analyses
15.5 Clinical Relevance of Molecular Characterization
References
16: Molecular Pathology of Endometrial Carcinoma on LBC Samples and Cell Blocks
16.1 Introduction
16.2 Liquid-Based Cytology and Cell Blocks in Endometrial Cancer Diagnosis
16.3 Molecular Tests in Liquid-Based Cytology and Cell Blocks: A New ERA
16.4 NGS (Next-Generation Sequencing)
References
17: Future Challenges and Perspectives of Endometrial Cytology
17.1 Background
17.2 Current Status and Future Perspectives of Digital Cytology
17.3 The Morphometric Approach to Endometrial Cytology Interpretation
17.4 Current Status and Future Perspectives of Flow Cytometry (LC-1000)-Assisted Endometrial Cytology Interpretation
17.5 Value of Cell-Free DNA Samples in the Follow-Up of Endometrial Malignancies
17.5.1 Molecular Study of Liquid-Based Pap Samples and of cf-DNA in Uterine Lavage Fluid
References
18: The Future Direction in Endometrial Oncology through the Liquid Biopsy
18.1 Introduction
18.2 Circulating Tumor DNA (ct-DNA) Evaluation for Monitoring Endometrial Cancer
18.3 Liquid-Based Pap Samples and ct-DNA in Uterine Fluid
18.4 Circulating Tumor Cells (CTCs) Evaluation for Monitoring Endometrial Cancer Patients
18.5 Circulating Tumor Cells (CTCs) Evaluation for Early Cancer Detection of Endometrial Cancer
18.6 Digital Imaging and Deep-learning Model and Liquid Biopsy
References
Index