What is a serrated adenoma, and is there any increased risk of malignancy or need for surveillance?
- Sessile serrated adenomas are premalignant flat (or sessile), often mucus-covered lesions predominantly seen in the cecum and ascending colon, that are thought to lead to CRC through an (alternate) serrated pathway.
- This differs from most CRCs, which arise from mutations starting with inactivation of the adenomatous polyposis coli (APC) gene.
- The serrated pathway has a predilection for the proximal colon.
- These lesions may be associated with BRAF or k-ras mutations, and CPG island methylation, which can lead to silencing of mismatch repair genes (MLH1), which could result in more rapid progression to malignancy in some individuals.
