Intramural, Extra-endometrial Epithelial Tumor of the Uterine Corpus Associated With Adenomyosis: A Case Report of Clear Cell Carcinoma.

An increasing number of case reports have been published regarding the occurrence of extra-endometrial epithelial tumors of the uterine corpus. The majority of these cases are endometrial cancers arising in adenomyosis (EC-AIA). This report describes the case of a postmenopausal woman who presented with a cystic tumor measuring 15 cm in diameter in the pelvic cavity. Prior to surgery, the tumor was considered to be a malignant ovarian cystic tumor with solid components based on imaging studies. A laparotomy was performed, revealing an intramural tumor of the uterine corpus. The intraoperative frozen section diagnosis was inconclusive. Consequently, a hysterectomy with bilateral salpingo-oophorectomy was performed without additional staging procedures. The final histopathological examination by permanent section revealed that the tumor was histologically composed of clear cell carcinoma, accompanied by adenomyotic foci in the surrounding myometrium. It is noteworthy that while most uterine intramural tumors are mesenchymal in nature, intramural extra-endometrial epithelial tumors such as EC-AIA can also manifest as uterine intramural tumors.