Polypoid colonic hamartomatous inverted polyp

We herein present a unique polyp diagnosed as polypoid colonic hamartomatous inverted polyp. Colonoscopic examination revealed a clover-like submucosal tumor about 30 mm in size with a long stalk at the mid-transverse colon. The polyp consisted of elongated crypts with cystic dilatation located in the submucosal layer. To the best of our knowledge, there have been no previous reports of the same type of pedunculated colonic polyp, similar in appearance to inflammatory myoglandular polyps but covered with a layer of normal mucosa possessing the muscularis mucosae at the uppermost surface of the polyp.