A Constellation of Rare Gynecological Malignancies and Familial Adenomatous Polyposis Gastrointestinal Adenocarcinoma: A Case Report.

Ovarian microcystic stromal tumors (MST) are a rare subtype of sex-cord stromal tumors. We are presenting a case of a MST arising in a patient with familial adenomatous polyposis (FAP) and concurrent colonic adenocarcinoma. During the patient's workup of an ampullary adenoma associated with her FAP, she was found to have an enlarged uterus with a thickened endometrium and an incidental pelvic mass on the fundus of the uterus. Subsequent imaging identified heterogenous bulky ovaries. This patient underwent surgical resection including a total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, bilateral pelvic sentinel lymph node biopsy during her planned total proctocolectomy and transduodenal ampullectomy. Extensive histologic and immunohistochemical investigations were completed and the final pathology report revealed a unique compilation of International Federation of Gynecology and Obstetrics Stage II, grade 1 endometrioid endometrial adenocarcinoma, bilateral ovarian MST, a sperate pedunculated mass favoring a diagnosis of uterine tumor resembling ovarian sex cord tumor (UTROSCT), 2 distinct adenocarcinomas of the colon (T2N0 and T1N0) and a tubular adenoma of the ampulla. The pathology showed the endometroid adenocarcinoma was β-catenin negative while the MST and UTROSCT both showed nuclear positivity with β-catenin. To our knowledge this is the first reported case of a UTROSCT with concurrent endometrial adenocarcinoma presenting with bilateral ovarian MST's and adenomatous polyposis coli gene positive FAP colon adenocarcinoma.