Gastric Synovial Sarcoma: A Case Report and Review of Literature.

Synovial sarcoma is monomorphic, mostly spindle cell sarcoma, characterized by t(X;18)(p11;q11) translocation, resulting in an SS18::SSX1/2/4 fusion gene. It occurs rarely in the gastrointestinal tract. Less than 50 gastric synovial sarcomas have been reported in the literature. We hereby present a 48-year-old male patient, who presented with weight loss and was found to have a mass in his stomach. Histopathological examination of the biopsy revealed a high-grade spindle cell sarcoma in the gastric wall. By immunohistochemistry, the tumor cells were diffusely positive for TLE1 and SS18-SSX, confirming the diagnosis of poorly differentiated synovial sarcoma. The patient underwent surgical resection, followed by adjuvant chemotherapy. He remained disease free for 6 months, following which the disease progressed and he developed metastatic lesions in the liver. Thus, although rare, synovial sarcoma occurs in the stomach and hence it should be included in the list of differential diagnoses of spindle cell sarcomas affecting stomach. A review of literature with treatment implications are discussed herewith.