[Serrated, hyperplastic and hyperplasia-like colorectal polyps]

The colorectal hyperplastic polyp has generally been considered a finding of no clinical significance. Recent research has, however, called attention to the existence of some variants of hyperplastic polyp which are potentially malignant. The term "advanced serrated polyp" has been coined for such cases, which comprise mixed hyperplastic/adenomatous tissue, serrated adenoma, and sessile serrated polyp, in contrast to the traditional hyperplastic polyp. Since epithelial dysplasia is an integrated component of mixed hyperplastic/adenomatous polyp and of the serrated adenoma, such a diagnosis would dictate control colonoscopy comparable to the guidelines for subjects with conventional adenomas. The cytology of the sessile serrated polyp is, however, closer to that of the traditional hyperplastic polyp, whereas the architecture mimics that of the serrated adenoma. For this reason, a consensus regarding the optimal management of such patients has not been obtained, but if the polyp is sizeable and located in the right colon, control should be considered. The small, usually left-sided traditional polyp as a rule needs no follow-up, but the context in which such a lesion is found and its morphology may influence the clinical decision. Future large-scale investigations of serrated colorectal polyps, including interobserver studies, will be required to identify histological details of clinical utility which can be adopted in daily routine practice.