Abstract
A 18-year-old girl visited the hospital due to hematochezia. Colonoscopy revealed a 6-mm Yamada type II polyp with stigmata of bleeding, and a shallow ulcer on top was found at the cecum base. The polyp was removed by snare polypectomy, and hematochezia stopped thereafter. Angiodysplasia was diagnosed histopathologically. Generally, angiodysplasia appears as a flat or elevated, bright-red lesion on endoscopy, with a polypoid shape being extremely rare. This case is significant because the lesion occurred at the youngest reported age and was the smallest that has been reported, and is the only polypoid arteriovenous malformation to be discovered in the cecum.