Pedunculated inverted hyperplastic polyp of the sigmoid colon treated with endoscopic polypectomy.

A case of inverted hyperplastic polyp of the sigmoid colon is reported. The patient was a 67-year-old woman who visited our hospital for further evaluation of constipation. Colonoscopy revealed a pedunculated polyp with linear central depression, about 12 mm in diameter, in the sigmoid colon. Excluding the polyp, there was no lesion in the colorectum. Endoscopic polypectomy was performed. Histological examination of the specimen revealed a stalked polyp that had scattered goblet cells and elongated tubules with serrated profiles in the superficial portion. The nodules of deep tubules impinged on the muscularis mucosae. Proliferation of fibromuscular tissue was not seen in the polyp. There was no evidence of malignancy. This polyp was diagnosed as an inverted hyperplastic polyp. Pedunculated-type inverted hyperplastic polyp of the colon is rare.