Serrated lesions of the colorectum, a new entity: what should a clinician/ endoscopist know about it ?

Serrated polyps of the colorectum have received much attention in recent literature. Several classifications have been proposed and created considerable confusion. Morphology and molecular biology have greatly contributed to the better identification of these entity. The recently published WHO classification, proposed using the term of "serrated polyp" as a generic term and defined sporadic serrated polyps as "a heterogeneous group" of lesions characterized morphologically by a serrated (sawtooth or stellate) architecture of the epithelial component which include hyperplastic polyps (HP), sessile serrated adenomas/polyps (SSA/P) and traditional serrated adenomas (TSA). With the development of molecular biology, it is now clear that the serrated pathway is one of the new carcinogenic pathways in the colon. There is now strong evidence that some serrated polyps correspond to precursors of some sporadic colorectal cancer (CRC). The aim of this article is to summarize the present data concerning the morphological and molecular characteristics of these serrated lesions and to give some recommendations for the management of such lesions.