Gastrointestinal Stromal Tumor with Mesenteric Localization Fistulized to Proximal Jejunum Causing Massive Rectal Bleeding

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal system. These non-epithelial tumors originate from the muscularispropria layer of the wall of the gastrointestinal tract. Their most common locations of origin are the stomach and small intestine. Rarely, they may originate from the retroperitoneum or abdomen, and may have no connection with the gastrointestinal system. They are usually incidentally detected in endoscopic and radiological examinations of the gastrointestinal system or during surgical treatment of emergency conditions such as hemorrhage, obstruction, or organ perforation. In this paper, we report a 59-year-old man with GIST located in the proximal jejunum that caused massive bleeding owing to its rarely encountered location. Histopathological examination made the definitive diagnosis, and the patient underwent total excision of the mass and the resection of a 20-cm jejunal segment