Closed Perforation of Small Bowel Caused by Primary Intra-abdominal Synovial Sarcoma

Synovial sarcoma is a rare and aggressive tumor, typically found in the extremities, with intra-abdominal cases being exceptionally uncommon. We present a 47-year-old male with abdominal pain and significant weight loss, whose imaging revealed a retroperitoneal mass originating from the duodenojejunal flexure. Computed tomography demonstrated a lobulated mass with heterogeneous enhancement, cystic and necrotic areas, and perilesional lymphadenopathy. Despite extensive imaging, definitive diagnosis required histopathological confirmation. Intraoperatively, a closed-loop perforation and vascular invasion rendered the tumor unresectable. Given the extreme rarity and diagnostic challenges of intra-abdominal synovial sarcoma, a multidisciplinary approach is essential. Comprehensive radiological evaluation, assessing mass morphology, vascular involvement, resectability, and metastatic potential, is crucial for accurate diagnosis and treatment planning. This case highlights the importance of advanced imaging in managing rare abdominal malignancies.