Mesonephric-like adenocarcinoma arising from endometrioid adenofibroma in a patient with in-utero exposure to diethylstilbestrol: A case report

Mesonephric-like adenocarcinomas are newly classified rare neoplasms of the upper genital tract. They share identical features with mesonephric adenocarcinomas, with the exception of location. There is ongoing discussion on whether mesonephric-like adenocarcinomas arise from mesonephric remnants or are of Müllerian origin. A 65-year-old woman (G2P1) presented with pelvic pain. Transvaginal ultrasound revealed multiple fibroids, and a robotic total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was planned. Intraoperatively, a complex mass with cystic and solid components was found on the left ovary, which also adhered to the rectosigmoid colon. Pathologic reports documented mesonephric-like adenocarcinoma that appeared to be arising in association with an endometrioid adenofibroma. This case is notable due to the patient's unique background of in-utero exposure to diethylstilbestrol (DES) and multiple gynecological malignancies within her mother, as well as the associated endometrioid adenofibroma. This case contributes evidence to two seemingly opposing theories of mesonephric-like adenocarcinoma histogenesis: the mesonephric remnant theory (supported by the patient's DES exposure), and the Müllerian theory (supported by the associated endometrioid adenofibroma).