Synchronous ovarian and uterine mesonephric-like carcinoma that potentially arose from endometrioid adenofibroma: A case report.

Mesonephric-like carcinoma histologically resembles mesonephric adenocarcinoma (MA) of the cervix. MA arises from mesonephric duct remnants. However, the origin of mesonephric-like carcinoma is not extensively studied because of its rarity. Here, we present a case of synchronous ovarian and uterine mesonephric-like carcinoma that potentially arose from endometrioid adenofibroma. A 69-year-old woman presented with an abdominal mass with no genital bleeding. She underwent simple total abdominal hysterectomy and bilateral adnexal resection. Histological and immunohistochemical analyses were consistent with mesonephric-like carcinoma involving both ovaries and the uterus. Endometrioid adenofibroma was present in both ovaries, while adenomyosis was observed in the uterus. The glandular duct of the endometrioid adenofibroma in the right ovary had areas suggestive of precursor lesions of mesonephric-like carcinoma. All tumors exhibited the KRAS G12D mutation. These findings suggest that the origin of the mesonephric-like carcinoma was the Müllerian duct, and that the ovarian and uterine tumors were monoclonal.