Sessile serrated (polyp) lesion

A sessile serrated lesion (SSL) is a premalignant flat (or sessile) lesion of the colon, predominantly seen in the cecum and ascending colon.

Sessile serrated polyp (SSP)

Sessile serrated adenoma (SSA)

SSLs are thought to lead to colorectal cancer through the serrated pathway.

Multiple SSLs may be part of the serrated polyposis syndrome.

SSLs are generally asymptomatic. 

They are typically identified on a colonoscopy and excised for a definitive diagnosis and treatment.

Serrated polyposis syndrome is a relatively rare condition characterized by multiple and/or large serrated polyps of the colon. 

Serrated polyps include serrated  sessile lesions, hyperplastic polyps, and traditional serrated adenomas. 

Serrated  sessile lesions are diagnosed by their microscopic appearance.

They are characterized by basal dilation of the crypts, basal crypt serration, crypts that run horizontal to the basement membrane and crypt branching. 

Basal dilation of the crypts is the most common finding.

Conventional colonic adenomas-tubular adenoma, and villous adenoma have nuclear changes: nuclear hyperchromatism, nuclear crowding, elliptical/cigar-shaped nuclei, not seen in sessile serrated lesions.


Complete removal of a SSL is considered curative.

Several SSLs confer a higher risk of subsequently finding colorectal cancer and warrant more frequent surveillance. 

The surveillance guidelines are the same as for other colonic adenomas. 

The surveillance interval is dependent on the number of adenomas, the size of the adenomas, and the presence of high-grade microscopic features.

Sessile serrated lesions account for about 25% of all serrated polyps.

Advanced SSLs with cytological dysplasia are rare in younger patients,and progression of SSLs appears to be linked with ageing.

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