Strumal Carcinoid Presenting as Large Pelvic Mass: A Rare Case and Review of Literature

Strumal carcinoid is an unusual rare ovarian teratoma characterized by the presence of thyroid tissue with a carcinoid tumor. We report a case of a 60-year-old nulliparous woman, who presented with complaints of a decrease in appetite, urinary frequency, and left lower extremity edema. By ultrasound of the abdomen, a large multiloculated cystic lesion occupying almost the entire pelvis and measuring 24 x 14 x 20 cm with internal debris concerning either uterine or ovarian cystic carcinoma was seen. By MRI, it was confirmed to be an ovarian lesion. Labs revealed elevated cancer antigen 125 (CA125) of 105 U/ml and carcinoembryonic antigen (CEA) of 6.4 ng/ml. The patient underwent surgery and the intraoperative consultation confirmed teratoma with a neuroendocrine component. Grossly, it was a multicystic ovarian mass and on sectioning, it had partial solid and cystic areas with clear to mucoid fluid. Histopathology showed foci of ectopic thyroid tissue admixed with foci of well-differentiated neuroendocrine tumor, grade 1 (carcinoid) displaying insular and trabecular patterns consistent with the diagnosis of strumal carcinoid (monodermal teratoma). Thyroid transcription factor-1 (TTF-1) and thyroglobulin immunostains highlighted ectopic thyroid tissue and synaptophysin highlighted neuroendocrine component. Strumal carcinoids are almost invariably benign and pathologic staging is not warranted. Treatment of strumal carcinoid is salpingo-oophorectomy.