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Even Expert Pathologists Have Only Moderate Agreement Regarding Differentiating Sessile Serrated Lesions From Hyperplastic Polyps

Douglas K. Rex, MD, MASGE, reviewing Vennelaganti S, et al. Gastroenterology 2020 Sep 18.

Current recommendations for measurement of the adenoma detection rate (ADR) recommend that sessile serrated lesions (SSLs; also called sessile serrated adenomas and sessile serrated polyps) not be counted toward the ADR because there is too much interobserver variation among pathologists in differentiating hyperplastic polyps (HPs) from SSLs. In an update of this issue, 8 experienced GI pathologists – 4 from the U.S. and 4 from Europe – met and discussed pathologic criteria for SSLs and then evaluated 41 HPs, 45 SSLs, 21 SSLs with dysplasia, and 13 traditional serrated adenomas (TSAs). The kappa values for interobserver agreement were moderate at 0.44 for SSLs, 0.55 for HPs, 0.4 for SSLs without dysplasia, 0.49 for SSLs with dysplasia, and 0.43 for TSAs. Kappa values were slightly higher for American versus European pathologists. Whole-length serration and crypt distortion were predictors of SSL diagnosis.

Douglas K. Rex, MD, FASGE


These data clearly indicate that differentiation of SSLs from HPs is still a problem if we can achieve only moderate agreement among expert pathologists. Further, lower kappa values are typically reached when consecutive lesions are used (more representative of the typical distribution of serrated lesions encountered during colonoscopy) and when only lesions <1 cm in size are considered (a more relevant group because many clinicians consider any serrated lesion, including hyperplastic polyps, to be advanced if ≥10 mm). Thus, it is still incorrect to include sessile serrated lesions/adenomas/polyps in the ADR calculation used in clinical practice.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.


Vennelaganti S, Cuatrecasas M, Vennalaganti P, et al. Moderate inter-observer agreement among pathologists in differentiation of sessile serrated from hyperplastic polyps. Gastroenterology 2020 Sep 18. (Epub ahead of print) (

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