Hyperplastic-like Colon Polyps That Preceded Microsatellite-Unstable Adenocarcinomas

Abstract

We compared hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas to incidental hyperplastic polyps to identify distinguishing morphologic criteria. The study group included 106 hyperplastic-like, nonadenomatous, serrated polyps, most from the ascending colon in 91 patients; the control group included 106 rectosigmoid hyperplastic polyps from 106 patients in whom adenocarcinoma did not develop. Study group polyps had an expanded crypt proliferative zone, a serrated architectural outline that became apparent in the basilar crypt regions, basilar crypt dilation, inverted crypts, and a predominance of dysmaturational crypts (crypts with minimal cell maturation). In contrast, control group polyps had a proliferative zone confined to the basal crypt region, serrated architecture that became apparent in the superficial crypt region, rare to no basilar crypt dilation, and rare or no dysmaturational crypts. Hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas had a distinctive constellation of morphologic features related to altered and decreased cell function and control that resulted in dysmaturational crypts. Dysmaturation constitutes a range of morphologic alterations, some of which overlap with incidental-type innocuous hyperplastic polyps. The morphologic features described herein provide initial guidelines to identify this potentially important subset of premalignant serrated-like polyps.

Differential clinicopathological features in microsatellite instability-positive colorectal cancers depending on CIMP status

“…These phenotypic differences between CIMP+ and CIMP− microsatellite-unstable tumors reflect not only a difference in gene expression profiles between them but also a difference in the morphological multistep progression pathways. Hereditary MSI+ CRCs are known to develop through tubular adenomas with or without villosity [30], whereas CIMP+/ MSI+ CRCs are generally thought to arise on a background of sessile serrated adenoma [10,31,32]. However, it needs to be pointed out that although there were statistical differences in some of the histological features, there is great overlap between categories, and some of the features are more or less common in the MSI cases regardless of CIMP status (for example, signet ring appearance shows a significant difference; yet, it is a feature which is absent in a vast majority of both CIMP− and CIMP+ carcinomas (3.7% and 27%, respectively)); hence, these features are of much clinical or diagnostic significance.…”

Over-expression of cathepsin E and trefoil factor 1 in sessile serrated adenomas of the colorectum identified by gene expression analysis

“…The diagnostic criteria for SSAs were based on the recently published criteria relying mainly on polyp architecture [10,23,24]. The architectural features which were assessed included crypt branching, horizontal dilatation of basal crypts and presence of serration at the base of the crypts.…”

Mucin core protein expression in serrated polyps of the large intestine

“…They are also frequently associated with BRAF mutations and abnormal DNA methylation [5][6][7]. SSAs are thus considered to be precursors of some populations of microsatellite instability high (MSI-H) colorectal carcinomas [1].…”