A case of mixed carcinoma of the endometrium

Background : The mixed carcinoma of the corpus uteri is a rare tumor classified as a special type of carcinoma of the corpus uteri, and there have been only a few cytopathological reports in Japan. We encountered a patient with atypical cells in cytological preparations but histologic typing was difficult. Case : In a 66-year-old woman, a poorly differentiated adenocarcinoma of the corpus of the uteri was the initial diagnosis based on cytological preparations of specimens collected from the uterine cervix and endometrium, but clear cell adenocarcinoma was diagnosed on examination of an endometrial biopsy specimen. A simple total hysterectomy was performed, and the histological diagnosis was mixed adenocarcinoma, mainly endometrioid adenocarcinoma with a component of clear cell adenocarcinoma. Conclusions : The incidence of mixed carcinomas of the corpus uteri including clear cell adenocarcinoma is low. However, its possibility should be considered if atypical cells suggesting clear cell adenocarcinoma or those with atypical naked nuclei are observed in addition to atypical cells suggesting endometrioid adenocarcinoma in an endometrial cytology preparation.