Fibroblastic Polyps: A Novel Polyp Subtype in Cowden Syndrome.

Cowden syndrome (CS) represents one possible phenotype of the PTEN gene mutation, and it can cause hamartomas throughout the gastrointestinal tract, with a predisposition for malignancy. Fibroblastic polyps have not been associated with CS. A 45-year-old woman with CS presenting for colonoscopic surveillance was found to have multiple sessile polyps throughout the transverse, descending, and sigmoid colon, all 2-5 mm in diameter. Based on the morphologic features and the immunohistochemical profile, these lesions were classified as fibroblastic polyps. This polyp subtype is recognized as a benign process of the colonic mucosa but is a novel histologic observation in the setting of CS.