[Correlation between clinical, dermatoscopic, and histopathologic variables in atypical melanocytic nevi]

Abstract

Introduction: Atypical melanocytic nevi are acquired melanocytic lesions that were described for the first time by Clark in studies of melanocytic nevi in patients with melanomas. Today, the use of dermatoscopy has made identification of this type of nevus much easier.

Objective: Our aim was to study the correlation between the clinical, dermatoscopic, and histopathologic findings of melanocytic nevi and compare our findings with those of previous studies. We also aimed to investigate the value of dermatoscopy for identifying atypical melanocytic nevi.

Material and methods: In this cross-sectional, observational study, 200 melanocytic lesions were analyzed in 166 patients examined between January 1, 2005 and December 31, 2005. We recorded the clinical, dermatoscopic, and histopathologic characteristics of each lesion and established the correlation between the different findings on a case-by-case basis. We then determined the agreement between diagnoses and assessed the value of dermatoscopy for identifying atypical melanocytic melanoma.

Results: The clinical characteristics associated with atypical histology were a macular component (P < .001), irregular borders, and presence of 3 or more colors. Asymmetry, diameter greater than 5 or 6 mm, and progression were not associated with atypical histopathologic characteristics (P > .05). Agreement between clinical and histologic diagnosis was weak (kp = 0.38), whereas the agreement between dermatoscopic and histologic diagnosis was moderate (kp = 0.52). The area under the receiver operating characteristic curve for the model that included dermatoscopy was larger than that for the model that only included clinical data, and this difference was statistically significant.

Conclusions: Atypical clinical features were not found to correspond to atypical histology. Dermatoscopy improved the accuracy of clinical diagnosis of atypical melanocytic nevus.