Clear cell adenocarcinoma of the cervix and its mimickers - A series of 19 cases from a tertiary care referral centre in India

Clear cell adenocarcinoma (CCAC) of cervix is a rare subtype of endocervical adenocarcinoma that accounts for 4% of all cervical adenocarcinoma with many morphological mimickers. Retrospectively study cases of cervical clear cell adenocarcinoma of the cervix. Clinical profile and pathological features of CCAC of the cervix diagnosed between 2018-2022 were retrospectively analyzed.The database of the Department of Pathology of our institute was systematically searched for patients diagnosed with clear cell adenocarcinoma of the cervix during 2018-2022.A total of 19 patients were studied with the mean age of patients being 53.72 years (range 25 -84 yrs,standard deviation-25.9) and median tumor size being 5.6cm. Lymph node metastasis was identified in 33.3% and distant metastasis were seen in 20% of the cases. Staging could not be done in 4 cases.FIGO staging of the cases included IB1(2 cases), IB2(2 cases), IIB (3 cases),IIIA (1 case)IIIB(4 cases),and IV(3 cases). On histopathological evaluation, heterogeneous architectural pattern comprising of tubulocystic, solid, and papillary patterns were seen in 13 cases (13/19,68.4%). Pure tubulocystic (3/19,15.7%), pure papillary (2/19,10.5%), and pure solid patterns (1/19,5.3%) were also identified. Tumor cells with clear cytoplasm ranged from 5% to 95%. Nuclear atypia was moderate to marked in all the cases (19/19,100%). Mitotic activity varied from 1/10hpf to 20-22/10hpf. By immunohistochemistry, tumor was positive for Napsin A in all the cases,p16INK4a was negative in majority of cases (15/19,78.9%) and ER was negative in 14 cases (14/19,73.7%) .p53 showed wild type staining except for one case . Clear cell adenocarcinoma being a rare subtype of cervical adenocarcinoma, needs to be differentiated from other Human Papilloma Virus(HPV) independent adenocarcinomas (gastric and mesonephric types) and benign entities such as endocervical glandular Arias-Stella reaction. Judicious use of a panel of immunostains is often helpful.