An inverted hyperplastic polyp with a characteristic colonoscopic appearance.

A 65−year−old man was referred to our de− partment for polypectomy. A polyp, 20 mm in diameter, was found in the as− cending colon on colonoscopy (Figure1 a). The polyp surface was covered by charac− teristic multiple dimples, long thin ves− sels, and mucus. Chromoendoscopy with 0.4% indigo carmine enhanced the ap− pearance of the polyp surface dimples, and subsequent magnification revealed a type II pit pattern according to Kudo s criteria, leading us to a diagnosis of a large hyperplastic polyp (Figure 1 b). Most hy− perplastic polyps do not show multiple dimples over their entire surface, and so an unusual histological diagnosis, such as inversion, was suspected before removal of the polyp. Endoscopic mucosal resec− tion using an inject and cut technique was performed, and the polyp was resected en bloc. Histologically, it was indeed found to be an inverted hyperplastic polyp (Fig− ure 2).