Trichoblastomelanoma

Abstract

We present a 48-year-old man with a 1-year history of nodular lesion on the chest. On clinical examination, the tumor was ulcerated and had a translucent appearance with an erythematous halo. Histopathologic examination revealed a nodular lesion that comprised the upper half of the dermis and ulcerated the epidermis. The neoplasm was composed of 2 intermingled components: nests of atypical melanocytes and basaloid epithelial cells. Immunohistochemical stains confirmed 2 immunophenotypically distinct components. The melanocytic component expressed the usual melanocyte markers S100 protein, HMB45, Melan A, and MiTF1, whereas the second population of epithelial neoplastic cells expressed pan-cytokeratin-MNF116, Ber-Ep4, cytokeratin 14, beta-catenin, and pleckstrin homology-like domain, family A, member 1 positivity. On the basis of these immunohistochemical findings, a diagnosis of trichoblastomelanoma was established. Biphasic cutaneous neoplasms composed of melanocytes and epithelial cells are extremely rare, and to the best of our knowledge, this is the first description in the literature of a combination of trichoblastoma and melanoma in the same neoplasm.