ABSTRACT
Colorectal serrated lesions are a group of polyps/adenomas with serrated architecture, including hyperplastic polyp, sessile serrated lesion and sessile serrated lesion with dysplasia, traditional serrated adenoma, and unclassified serrated adenoma. Sessile serrated lesion and traditional serrated adenoma are precursors of serrated lesions progressing to colorectal cancer. Serrated lesions are characterized by genetic (BRAF or KRAS gene mutations) and epigenetic (CpG island methylator phenotype) alterations that synergistically drive colorectal mucosa to develop polyps or adenomas, and with malignant transformation into colorectal cancer. The complexity of serrated lesion makes it difficult to diagnose, easy to miss diagnosis and has a high malignant rate. This article reviewed the advances in research on colorectal serrated lesions from the aspects of endoscopic, pathological and molecular features.