PRAME expression in melanocytic proliferations with intermediate histopathologic or spitzoid features. Journal of cutaneous pathology Raghavan, S. S., Wang, J. Y., Kwok, S., Rieger, K. E., Novoa, R. A., Brown, R. A. 2020

Abstract

BACKGROUND: PRAME (PReferentially expressed Antigen in MElanoma) has shown utility in distinguishing melanoma from benign melanocytic lesions, but knowledge of its expression pattern in intermediate melanocytic and spitzoid proliferations is limited.METHODS: Immunohistochemical expression of PRAME was examined in 112 melanocytic proliferations with intermediate histopathologic or spitzoid features.RESULTS: Any intensity of PRAME staining in at least 60% of lesional melanocytes was determined as the best threshold for diffuse staining in this cohort. Nearly all non-spitzoid melanomas (23/24; 95.8%) demonstrated diffuse PRAME expression. PRAME was completely negative in 95.6% (43/45) of mitotically-active nevi, traumatized nevi, nevi with persistent/recurrent features, and dysplastic nevi. Most Spitz nevi (15/20) and atypical Spitz tumors (10/13) entirely lacked PRAME expression. One Spitz nevus, one atypical Spitz tumor, and one case of spitzoid melanoma (1/2) demonstrated diffuse PRAME expression.CONCLUSIONS: Although diffuse PRAME expression is generally limited to malignant melanoma, benign Spitz nevi and atypical Spitz tumors can infrequently express diffuse PRAME. PRAME immunohistochemistry can be useful in the evaluation of atypical melanocytic proliferations with intermediate histopathologic features but should be interpreted with caution in the setting of spitzoid neoplasms. This article is protected by copyright. All rights reserved.

View details for DOI 10.1111/cup.13818

View details for PubMedID 32700786