Extragonadal sex cord tumor with annular tubules in an umbilical hernia sac: a unique presentation with implications for histogenesis.

A sex cord tumor with annular tubules (SCTAT) was found incidentally in an umbilical hernia sac excised from a 66-year-old female. No ovarian lesions were visualized on a computerized tomographic (CT) scan of the pelvis. An exploratory laparotomy with total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic lymph node biopsies, and omentectomy likewise showed no gross evidence of tumor. Histologic examination revealed foci of SCTAT scattered in the omentum. The peritoneal washings were positive. The ovaries and pelvic lymph nodes were free of tumor. A second-look laparotomy following six courses of chemotherapy with cyclophosphamide, actinomycin D, and vincristine revealed microscopic tumor deposits in the base of the omental remnant, small bowel mesentery, anterior abdominal peritoneum, and meso-appendix. Clinically, the patient remains well following treatment with whole-abdominal radiation. To our knowledge, this is the first report of SCTAT in the umbilical region and the only case of SCTAT without an identifiable ovarian primary. The literature is reviewed, and the possible histogenesis of the tumor in this location is discussed.