Uterine retiform Sertoli-Leydig cell tumor report of a case providing additional evidence that uterine tumors resembling ovarian sex cord tumors have a histologic and immunohistochemical phenotype of genuine sex cord tumors

We report a case of a retiform Sertoli-Leydig cell tumor of intermediate differentiation presenting as a uterine intracavity polypoid mass in a 63-year-old woman. In contrast to sertoliform endometrioid carcinoma and to hitherto reported uterine tumors resembling ovarian sex cord tumors (UTROSCTs), which are primarily characterized by tubular glands and solid tubules, this tumor, which most likely represents a UTROSCT, showed a large spectrum of histologic features typical of a genuine retiform Sertoli-Leydig cell tumor. The diagnosis was confirmed by a battery of immunohistochemical stains, which also served as a tool for differential diagnosis with other neoplasms. The tumor cells were positive for broad spectrum keratin (CK) CK18, vimentin, calretinin, and progesterone receptor. Only a few isolated cells stained for inhibin. The tumor cells were negative for CK7, CK5/6, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125), thrombomodulin, 013 (CD99), melan A, alpha-fetoprotein (AFP), placental alkaline phosphatase (PLAP), α-1-antitrypsin, estrogen receptor, S100, neurone specific enolase (NSE), chromogranin, synaptophysin, desmin, caldesmon, and CD10. Divergent differentiation of uterine cells seems to be the most likely pathogenetic mechanism. To the best of our knowledge, no UTROSCT showing such a variety of histologic features indicative of a true sex cord tumor has been reported before.