Primary Gastric Synovial Sarcoma: A Report of a Rare Case and Review of the Literature.

Synovial sarcoma is typically a soft tissue neoplasm, but gastrointestinal tract involvement is unusual. When occurring in the stomach, its appearance may overlap with more common spindle cell tumors such as gastrointestinal stromal tumors (GISTs). We describe the case of a 44-year-old woman who presented with anemia and abdominal pain. Radiologic imaging revealed a large gastric mass with extragastric extension, initially interpreted as a possible GIST. Subsequent histopathological examination demonstrated a monophasic spindle cell tumor, and the immunohistochemical profile was consistent with synovial sarcoma. Molecular analysis further supported the diagnosis. This report emphasizes the diagnostic challenges of gastric synovial sarcoma and highlights the critical role of combining histopathology, immunohistochemistry, and molecular testing to achieve an accurate classification. Awareness of this rare entity is essential for timely diagnosis and optimal management.