A Rare Case of Multifocal Ileal and Mesenteric Gastrointestinal Stromal Tumors With Spontaneous Rupture.

Gastrointestinal stromal tumors (GISTs) most commonly present with gastrointestinal bleeding or as an abdominal mass, whereas spontaneous rupture with pneumoperitoneum is distinctly uncommon and portends an adverse prognosis. A 51-year-old man presented with acute hematemesis and melena of two days' duration. Contrast-enhanced computed tomography of the abdomen demonstrated a large, lobulated, heterogeneously enhancing ileal mass with central necrosis, intralesional gas, direct communication with adjacent small-bowel loops, and free intraperitoneal air consistent with tumor rupture and pneumoperitoneum. Multiple additional mesenteric and pelvic masses with smooth peritoneal thickening and mild ascites suggested peritoneal dissemination. Emergency laparotomy confirmed tumor rupture with feculent peritonitis and widespread peritoneal seeding. Histopathology established a high-grade, multifocal GIST (pT4(m)N0) with spindle-to-epithelioid morphology, increased mitotic activity, necrosis, strong CD117 and DOG1 positivity, and an elevated Ki-67 labeling index. This case highlights the characteristic radiologic features of ruptured GIST and demonstrates close radiologic-pathologic concordance in an aggressive presentation.