Serrated polyps of right colon: guilty or innocent?

In recent years a lot of interest has been focused on a specific category of polyps, the so-called serrated polyps which until recently were categorized with the hyperplastic or mixed polyps and were thought to have no risk of malignant transformation. Recently though, the serrated pathway of carcinogenesis was discovered and destroyed this myth. It is believed that up to one third of all colorectal cancers arise through the serrated pathway; these cancers occur more often in the proximal colon and have specific molecular characteristics. Specific subtypes of serrated polyps (mainly the sessile serrated adenomas/polyps) are thought to be precursor lesions of these cancers. The prevention of these cancers is a challenge for gastroenterologists because their location and endoscopic characteristics renders them difficult to detect. Also, although there is a clear need for creating a specific post-polypectomy surveillance program for these lesions, to date there have been no guidelines for surveillance with a high level of evidence. In this article the main molecular, endoscopic, histological and epidemiologic characteristics of these lesions are presented, as well as recommendations for surveillance.