Sessile serrated polyps: an important route to colorectal cancer.

The serrated neoplastic pathway accounts for approximately 30% of colorectal cancers. Characterized by mutations in the oncogene BRAF, DNA promoter hypermethylation, and microsatellite instability, cancers arising in this pathway develop via serrated polyp intermediates. Serrated polyps represent a heterogeneous group of lesions with distinct genetic, molecular, and clinical features. Sessile serrated polyps (also called sessile serrated adenomas) have emerged as the key intermediates in this pathway. These lesions have malignant potential and are often difficult to detect endoscopically, thus contributing to the development of interval cancers. Recent advances in the understanding of sessile serrated polyps have led to new histologic classifications, increased endoscopic recognition, and changes in clinical management recommendations. This article focuses on sessile serrated polyps as a unique and important route to colorectal cancer.