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.