抄録
A 62-year-old man presented with black stool. Laboratory data showed anemia. Contrast-enhanced computed tomography revealed a hypervascular tumor in the pelvic cavity measuring 50×60 mm in size, with air pooling in the central portion of the tumor. A small bowel series demonstrated gastrografin accumulation through the fistula on the opposite side of the mesenterium, 30 cm from the ligament of Treitz. Single-balloon endoscopy showed a low-growing elevated mucosa-like submucosal tumor, which showed a pinhole formation in the center.
Partial jejunectomy was performed for resection of the tumor. The solid tumor appeared to arise from the jejunum on the opposite side of the mesentrium. The pathological diagnosis was GIST, because immunohistochemical analysis showed positive staining for c-kit. Interestingly, the surface of the fistula was covered with ordinary jejunal mucosa. Based on this finding, it is considered that the GIST probably arose from a jejunal diverticulum.
