Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal (GI) tract. These tumors are frequently small, asymptomatic and found incidentally. GI bleeding is a common complication of these tumors, but small sized, very low risk GIST rarely complicated with fatal bleeding. In this report, we describe a 42-year-old woman with a jejunal GIST accompanied by severe GI bleeding. She presented with melena and an angiographic embolization was performed for a jejunal mass with bleeding. However, rebleeding was suspected after an angiographic embolization and an emergent segmental resection for the bleeding mass was performed. She was finally diagnosed as a 1.8 cm sized very low risk GIST in jejunum. In conclusion, physician should consider that even very low risk GIST can be the cause of GI bleeding when there is severe bleeding.

Gastrointestinal stromal tumors (GISTs) are common mesenchymal tumors that arise in the wall of the gastrointestinal tract. We report a case of obscure gastrointestinal bleeding due to a GIST of the jejunum successfully documented by videocapsule endoscopy (VCE) and single-balloon enteroscopy (SBE). A 36-year-old man with hematochezia was referred for further evaluation of no evidence of bleeding focus on esophagogastroduodenoscopy and colonoscopy. A VCE showed a suspicious ulcerative hyperemic mass that located in about 1 hour apart from duodenal second portion. SBE revealed a nonbleeding 4×2 cm mass with an ulcer at the proximal jejunum. The patient underwent laparoscopic resection without complication. Histological examination revealed a well circumscribed, dumbbell-shaped firm mass comprised of spindle cells. Immunohistochemical staining for CD 117 was diffusely positive, whereas staining for S-100, CD 34 and MIB-1 was all negative. It was confirmed to be a low-grade GIST at the proximal jejunum.

A gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract and expresses CD117, a c-kit proto-oncogene, which can be detected immunohistochemically. We reported a GIST of the rectum of a 61-year-old-woman who had visited emergency room complaining of constipation over one week. Upon rectal examination, a round hard mass was palpated. Colonoscopy showed a 7×5 cm sized protruded lesion with surface ulceration on a rectum, adjacent the anus. And abdomen computed tomography revealed the soft tissue mass compressing anterolateral wall of the rectum and these findings suggest possibility of rectal submucosal tumor such as GIST. The patient had been treated with a ultra anorectal anastomosis with loop ileostomy. Immunohistochemical studies on the surgically resected specimen showed c-kit (+) and CD34 (+). The final diagnosis was a GIST of the rectum. She was grouped into high risk and she has been given adjuvant chemotherapy with Imatinib.