The most frequent complication occurring in continent ileo-anal pouches after colectomy for ulcerative colitis (UC) is pouchitis. Recurrences of adenomas or carcinomas in pouches of familial adenomatous polyposis (FAP) patients are exceptional, whereas in those with ulcerative colitis dysplasia it is a very rare occurrence. We describe the case of a young woman who developed a mass in a J pouch three years after its construction following colectomy for ulcerative colitis. Histological and immunohistochemical studies showed that this mass had the features of an inflammatory fibroid polyp. A review of the literature of lesions observed in continent ileo-anal pouches after colectomy for UC would suggest that this lesion is an exceedingly rare complication of those devices.