Last update:
16-Jul-2014

Colonic serrated polyps can be classified into hyperplastic polyps, sessile and traditional serrated adenomas and mixed polyps, with a prevalence of 30%, 3.9%, 0.7% and 0.7% of all polyps, respectively, although there is absence of consensus among pathologists regarding their nomenclature, classification and morphological features. Hyperplastic polyps are classified into microvesicular, goblet cell rich and mucin poor subtypes, characterized by the presence of goblet cell and proliferation zone enlargement in the upper intestinal crypts. Sessile serrated adenomas are characterized by dysplasia, crypt compartmentalization, aberration and irregular expression of cell differentiation and proliferation markers, while traditional serrated adenomas are characterized by dysplasia and ectopic crypts. The specific diagnosis of serrated polyps is very important because of their differing risk of malignancy and this requires thorough histopathological examination of the specimen and detailed clinical information. Colorectal cancer appearing between two scheduled colonoscopies ("interval carcinoma") mainly arises from serrated polyps which were missed at diagnosis or had a higher transformation rate than that of conventional adenomas. The low detection rate of serrated polyps is attributed to their small size and sessile appearance, the right-sidedness of the lesions and inadequate cecal intubation during colonoscopy. Equally important are the absence of such endoscopic applications as narrow band imaging and chromoendoscopy and poor technical and theoretical skills on the part of the endoscopist. Serrated polyps of the colon require endoscopic resection and monitoring, which should be at least as frequent as that for conventional adenomas.

Key words: Diagnosis, Dysplasia, Serrated polyp, Surveillance.