Colon, Traditional serrated adenoma

Traditional serrated adenomas (TSAs) are uncommon polyps in the gastrointestinal tract, most commonly found in the left side of the colon. They are the least common of the serrated polyps, after hyperplastic polyps and sessile serrated adenomas. These lesions have a villiform-like architecture with serrated eosinophilic surface epithelium. Ectopic crypt formation (short crypts oriented at right angles to main crypt without reaching the muscularis mucosae) is a characteristic feature. The nuclei are usually pencillate with evenly dispersed coarse chromatin with inconspicuous nucleoli (if present). Adenomatous dysplasia is more common in these lesions compared to the less studied serrated dysplasia. These lesions commonly have RAS mutations, in contrast to their sessile serrated counterpart, which typically have BRAF mutations.

See Related Content for references:

1) Geramizadeh, B., Robertson, S. J Gastrointest Cancer. 2017 Jun 22