Diagnosis and management of a pelvic solitary fibrous tumor in a postmenopausal woman – a case report

BACKGROUND: Solitary fibrous tumors, previously known as hemangiopericytomas, originate from mesenchymal tissue and can occur at many body sites, such as the thorax, head and neck, retroperitoneal space and abdomen. These tumors are generally rare and pelvic location is extremely uncommon. Consequently, pelvic solitary tumors could be mistaken for ovarian cancer in menopausal women. This report presents a case of pelvic solitary tumor to highlight the importance of considering this diagnosis in a postmenopausal woman presenting with a solid pelvic mass, normal tumor markers and no ascites. CASE: A 54-year-old woman presented with amenorrhea, abdominal pain, constipation, nausea, vomiting, and frequency of urination. On examination she had a pelvic mass of approximately 20–24 weeks in size. Ultrasound and computed tomography imaging showed a well-defined, round, centrally hypodense, irregular thick and peripheral, enhancing solid mass originating from the left ovary. Carcinoembryonic antigen, carbohydrate antigen-125, and carcinoembryonic antigen 19–9 were all normal. Intraoperatively the tumor was attached to the peritoneum and mesentery. Part of the large bowel, including the sigmoid colon, were attached to it. The exact origin of the tumor could not be ascertained during surgery. The tumor was successfully excised, and specimen sent for histology and immunochemistry analysis. The definitive diagnosis was confirmed with immunochemistry. The patient had an uneventful postsurgical course and was discharged on day 4 after surgery for routine gynecological follow-up. CONCLUSION: Solitary fibrous tumor is very rare; however, the diagnosis should be considered in a postmenopausal woman with solid pelvic mass, normal tumor markers and no ascites.