Prior knowledge of the clinical picture does not introduce bias in the histopathologic diagnosis of melanocytic skin lesions

J Cutan Pathol. 2015 Dec;42(12):953-958. doi: 10.1111/cup.12589. Epub 2015 Oct 2.

Abstract

A common debate among dermatopathologists is that prior knowledge of the clinical picture of melanocytic skin neoplasms may introduce a potential bias in the histopathologic examination. Histologic slides from 99 melanocytic skin neoplasms were circulated among 10 clinical dermatologists, all of them formally trained and board-certified dermatopathologists: 5 dermatopathologists had clinical images available after a 'blind' examination (Group 1); the other 5 had clinical images available before microscopic examination (Group 2). Data from the two groups were compared regarding 'consensus' (a diagnosis in agreement by ≥4 dermatopathologists/group), chance-corrected interobserver agreement (Fleiss' k) and level of diagnostic confidence (LDC: a 1-5 arbitrary scale indicating 'increasing reliability' of any given diagnosis). Compared with Group 1 dermatopathologists, Group 2 achieved a lower number of consensus (84 vs. 90) but a higher k value (0.74 vs. 0.69) and a greater mean LDC value (4.57 vs. 4.32). The same consensus was achieved by the two groups in 81/99 cases. Spitzoid neoplasms were most frequently controversial for both groups. The histopathologic interpretation of melanocytic neoplasms seems to be not biased by the knowledge of the clinical picture before histopathologic examination.

Keywords: clinical information; clinicopathologic correlation; dermoscopy; histopathologic diagnosis; melanocytic skin neoplasms.