Endocervical Adenocarcinoma: Comprehensive Histological Review and Re-classification of 123 Consecutive Cases According to the Updated World Health Organization Classification of Female Genital Tumors

Background/Aim: The updated 2020 World Health Organization (WHO) classification divides endocervical adenocarcinomas (EACs) into human papillomavirus-associated (HPVA) and -independent (HPVI) tumors. The purpose of this study was to review our EAC cases and reclassify them according to the updated WHO classification. Patients and Methods: We reviewed the hematoxylin and eosin-stained slides of 123 EACs and reclassified them according to the updated WHO classification. Results: Eighty-one (65.9%) and 42 (34.1%) patients had HPVA and HPVI EACs, respectively. The usual (60/81; 74.1%) and gastric (31/42; 73.8%) types were the most common HPVA and HPVI EACs, respectively. Signet-ring cell (1/123; 0.8%), invasive stratified mucin-producing (10/123; 8.1%), clear-cell (4/123; 3.3%), mesonephric (3/123; 2.4%), and serous (1/123; 0.8%) types were uncommon. Unusual morphologies were seen, including microcystic, elongated, and fragmented patterns of stromal invasion, micropapillary growth patterns, and gastric-type adenocarcinoma in situ. Conclusion: We successfully reclassified all the examined cases based on morphology alone. The numbers and relative proportions of EAC histotypes were variable. We found some uncommon histotypes, as well as unusual but clinically important histological features.