Sessile Serrated Adenomas and Their Pit Patterns: We Must First See the Forest Through the Trees

Serrated lesions of the colorectum include hyperplastic polyps, which are non-neoplastic, and sessile serrated adenomas (SSAs, also known as sessile serrated polyps) and traditional serrated adenomas, which are premalignant. It is believed that up to 30% of colon cancers and many post-colonoscopy cancers arise from serrated neoplasms. Post-colonoscopy cancers have been found to have a molecular signature similar to SSAs, including CpG island methylation, BRAF mutations, and microsatellite instability. A novel pit pattern, Type II-O, has been demonstrated to have a high specificity for SSAs. Unfortunately, the sensitivity is too low to utilize a Type II-O pit pattern to determine which serrated lesion is neoplastic and needs resection. Moreover, there is significant endoscopist-related variability in the detection of serrated lesions of the colon. Efforts to improve the detection of serrated neoplasms are warranted.