Knowledge of the anatomical polyp location might bias the pathological classification of histologically equivocal colorectal serrated polyps - a consensus study performed by pathology trainees.

Colorectal serrated polyps (CSPs) comprise hyperplastic polyps (HPs), traditional (TSAs) and sessile (SSAs) serrated adenomas, as well as inflammatory cloacogenic polyps (ICPs). These lesions have typical anatomical locations and share a histomorphological overlap. In this study, we assessed the so far neglected issue as to what extent the histological classification of these lesions performed by pathology trainees is biased by the pathologists' knowledge of the polyp location in dependency on the duration of their training. To reach this aim, 49 CSPs were classified by three pathology trainees blinded to clinical data. In a second round of examination, the same raters were provided with the polyp location. A third round was conducted after a consensus conference. Intra- and inter-rater analyses were performed using Kappa (K) statistics and Spearman correlations. Our data suggest that the histological classification of CSPs performed by pathology trainees might be influenced in a clinically significant fashion by knowledge of the anatomical polyp location depending on the duration of their pathology training.