Serrated polyps of the colorectum: is sessile serrated adenoma distinguishable from hyperplastic polyp in a daily practice?

Abstract

The distinction between serrated polyps of the colon is complex, particularly between hyperplastic polyps (HP) and sessile serrated adenomas (SSA). Recent data show that SSA might be the precursors of serrated colonic cancers, underlining the necessity of identifying them. We characterized the demographic and pathologic characteristics of 102 serrated lesions among 321 polyps of the colorectum and determined if SSA can be microscopically distinguished from HP in biopsy material of a daily practice. There were 81 HP (79%) and 7 SSA (7%) of which one displayed lowgrade dysplasia. Only six serrated polyps (6%) could not be correctly classified. The main architectural criteria for distinguishing SSA from HP is the serrated feature along the crypt axis and the rarity of undifferentiated cells in the lower third of the crypts. SSA was significantly more often located in the right colon and larger (median, 11 vs 4 mm) than HP. SSA are rare serrated polyps that can be distinguished from HP based on their morphology, location in the right colon, and larger size. One SSA of our series showed low-grade dysplasia supporting the concept that this lesion might be a precursor of serrated adenocarcinoma.

Evaluación de la reproducibilidad del diagnóstico microscópico del adenoma serrado de sésil de colon

“…SSA represents 10% of all colonic polyps and around 20% of all serrated lesions (6). In this series, which included only polyps with serration, 3% and 16% of lesions were classified as SSAs by pathologist 1 and pathologist 2, respectively, which was consistent with the literature (14). These are significant percentages, thus failing to accurately diagnose these lesions represents an incorrect assessment of CRC risk for some patients, with consequences for CRC screening and post-polypectomy follow-up programs.…”

“…No study has specifically assessed the influence of the sampling method on diagnostic agreement; therefore no comparisons can be done. However, other authors have shown that the classification of serrated lesions is more difficult to apply in superficial and tangentially cut lesions, and in small and fragmented lesions (14), while an en-bloc excised lesion is easier to orientate and diagnose.…”

A Serrated Colorectal Cancer Pathway Predominates over the Classic WNT Pathway in Patients with Hyperplastic Polyposis Syndrome

“…28 Because HPs and SSAs are common findings in HPS and have been shown to be difficult to differentiate microscopically, all serrated polyps were included in the criteria. [31][32][33][34] Patients with a known germline APC mutation or a bi-allelic MUTYH mutation were excluded from the study. The study was conducted in accordance with the research code of the institutional medical ethical committee on human experimentation of the Academic Medical Center and in agreement with the Helsinki Declaration of 1975 as revised in 1983.…”

Improved molecular classification of serrated lesions of the colon by immunohistochemical detection of BRAF V600E

“…17,18 Owing to sampling issues, poor specimen orientation and a significant interobserver variation among pathologists, [19][20][21][22] the differential diagnosis of microvesicular hyperplastic polyps vs sessile serrated adenomas/polyps can be very challenging or even impossible. Especially, if we consider that for the differential diagnosis of microvesicular hyperplastic polyp vs sessile serrated adenoma/polyp, the presence of the appropriate morphologic criteria in just one crypt is considered as sufficient.…”