Malignant Melanocytic Matricoma: A Report of 2 Cases and Review of the Literature

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Background: To describe 2 cases of melanocytic matricoma with malignant histological features and systematically review previously reported cases of malignant melanocytic matricoma. Methods: Two cases of malignant melanocytic matricoma were identified from the practice of the authors. Additional 3 cases were identified in the literature. The clinical and pathological features of these 5 cases are described. Results: Malignant melanocytic matricoma occurs predominantly in sun-damaged skin of elderly individuals. The tumor is composed of atypical epithelial cells with brisk mitotic activity showing evidence of matrical keratinization and widespread positivity with beta-catenin. There is an admixed cytologically bland dendritic melanocytic component. To date, local recurrence has occurred in one case, but no cases of disseminated disease or death have been reported. Conclusions: Recognition of this rare tumor and separation from a range of diagnostic mimics is important to ensure adequate treatment by local excision and to allow further cases to be identified to better define the biological potential of this lesion.