Reproducibility of the Villous Component and High-grade Dysplasia in Colorectal Adenomas <1 cm
The presence of high-grade dysplasia (HGD) or villous component (VC) defines an advanced adenoma (AA) in patients with 1 or 2 adenomas <1 cm in size. Current consensus guidelines recommend that patients with AA undergo more intense postpolypectomy surveillance. In these clinical situations, the interobserver reliability in determining VC and HGD would play a major role in the credibility of these consensus guidelines. Therefore, the purpose of this study was to evaluate interobserver variability of VC and HGD in polyps <1 cm before and after the development of consensus criteria among gastrointestinal (GI) pathologists. Five GI pathologists independently evaluated 107 colorectal adenomas <1 cm, and classified them into tubular adenomas or adenomas with a VC (A-VC) and into low-grade dysplasia or HGD. Then a consensus conference was held and consensus criteria for VC and HGD were developed by group review. The same set of 107 slides were rereviewed independently by the same 5 GI pathologists. Interobserver variability using κ statistical analysis before and after the application of consensus criteria was assessed. A 1-sided z-test was used to determine whether κ scores increased after the consensus conference. Interobserver agreement before and after the consensus conference was poor for assessment of A-VC, HGD, and AA. These data calls into question the validity of basing clinical decisions on this distinction.
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- [Show abstract] [Hide abstract] ABSTRACT: Colorectal polyps are frequently encountered in daily pathology practice. The accurate diagnosis of these polyps forms a key component of clinical care, both in determining the malignant potential (and thus the follow-up interval for colonoscopy) as well as raising suspicion for polyposis syndromes. As such, the pathologist plays an instrumental role in the care of patients with colon polyps. This review highlights the histologic features of several commonly (and uncommonly) encountered colon polyps and provides genetic and clinical features of several polyposis syndromes that can be diagnosed (or at least suspected) when evaluating biopsies of colon polyps.