Duplication cyst of the small intestine found by double-balloon endoscopy: a case report.

A 35-year-old man was admitted due to bloody stool and anemia. The bleeding source could not be detected by esophagogastroduodenoscopy or colonoscopy. Double balloon endoscopy (DBE) revealed a diverticulum-like hole in which coagula stuck in the ileum at 1 meter on the oral side from the ileocecal valve. The adjacent mucosa just to the oral side of the hole was elevated like a submucosal tumor. The lesion was considered the source of bleeding and removed surgically. It was determined to be a cyst with an ileal structure on the mesenteric aspect accompanying gastric mucosa. The diagnosis was a duplication cyst of the ileum, which is a rare entity that can cause gastrointestinal bleeding. In the present case, DBE was used to find the hemorrhagic duplication cyst in the ileum.