Discordance in diagnosis of melanocytic lesions and its impact on clinical management: A melanoma referral center experience with 1521 cases

Context.-Accurate diagnosis of melanocytic lesions is fundamental for appropriate clinical management. Objective.-To evaluate the degree of discordance, if any, between histopathologic diagnoses of melanocytic lesions at referring institutions and at a tertiary referral cancer center and the potential impact of such discordance on clinical management. Design.-We retrospectively identified all patients referred to our comprehensive cancer center for evaluation of a melanocytic lesion from January 2010 to January 2011. For each patient, the histopathologic diagnosis from the referring institution was compared with the histopathologic diagnosis from a dermatopathologist at our center. Discordances were classified as major if they resulted in a change in clinical management and minor if they did not. Results.-A total of 1521 cases were included. The concordance rates were 72.2% (52 of 72) for dysplastic nevus, 75.0% (15 of 20) for all other types of nevi, 91.1% (143 of 157) for melanoma in situ, 96.1% (758 of 789) for invasive melanoma, and 99.6% (478 of 480) for metastatic melanoma. Major discordances were found in 20.2% of cases (307 of 1521), and minor discordances were found in 48.8% of cases (742 of 1521). Compared with the guideline-based treatment recommendation based on the referring-institution diagnosis, the guideline-based treatment recommendation based on the cancer center diagnosis was more extensive in 5.9% (89 of 1521) of patients and less extensive in 5.0% (76 of 1521) of patients. Conclusions.-Our findings underscore the importance of secondary histopathologic review of melanocytic lesions by expert dermatopathologists because significant changes in the diagnosis, tumor classification, and/or staging may be identified, thus, resulting in critical changes in recommendations for clinical management.