Omental synovial sarcoma mimicking an ovarian malignancy: A case report.

Synovial sarcoma is clinically rare, and cases of synovial sarcoma arising in the omentum are particularly rare. Only 3 cases have been reported in the literature to dtae, and they were associated with a poor prognosis. We herein report a rare case of aggressive primary omental synovial sarcoma presenting as an ovarian malignancy. A 53-year-old multigravida woman was referred to our hospital due to progressive abdominal distension. Magnetic resonance imaging revealed a large heterogeneous mass with an irregular component occupying the lower abdominal cavity, with an intact uterus. Intraoperative examination revealed a solid mass arising from the lower omentum. The diagnosis of omental synovial sarcoma was established based on postoperative pathological and immunohistochemical examination of the tumor. The patient underwent multiple surgical resection procedures due to the development of metastases in the liver, lungs and abdominal cavity and received adjuvant chemotherapy including doxorubicin-ifosfamide, pazopanib and trabectedin. Such rare neoplasms may be difficult to diagnose preoperatively based on radiological examinations alone. Thus, gynecologists should be aware of the possibility of omental synovial sarcoma, and combined surgical and chemotherapeutic interventions are required to control such aggressive tumors.