An arteriovenous malformation in the jejunum mimicking a gastrointestinal stromal tumor.

A 51-year-old man visited the tertiary-care hospital with a 2-week history of dizziness and dyspnea on exertion. The initial hemoglobin level was 5.8 g/dL, without any history of hematochezia or melena. The esophagogastroduodenoscopy (EGD) was normal. During colonoscopic preparation, the patient experienced hematochezia and became hypotensive. On angiography, no extravasation of contrast media was observed. A CT scan with angiography showed a small high-density area in the jejunal lumen, suggesting extravasation of the contrast media. Capsule endoscopy was performed, and oozing bleeding was suspected in the proximal to mid jejunum. The patient was referred to our hospital. Repeated EGD and CT enterography did not reveal any significant bleeding. An antegrade double balloon endoscopy was performed, and an approximately 2-cm-sized submucosal tumor with ulceration and a non-bleeding exposed vessel was observed in the mid jejunum. The presumed diagnosis was jejunal gastrointestinal stromal tumor. The mass was surgically resected, and the final histopathological diagnosis was arterio-venous malformation.