Lymphoepitheliomalike carcinoma of the skin. A case report with immunophenotypic analysis and in situ hybridization for Epstein-Barr viral genome.

Lymphoepithelioma is a malignant epithelial neoplasm of the nasopharynx. Similar malignancies--lymphoepitheliomalike carcinomas--of salivary glands, thymus, larynx, lung, stomach, and uterus have been described. We present here a case of lymphoepitheliomalike carcinoma of the skin in an 84-year-old woman. Histologically this neoplasm presented as a fairly discrete dermal aggregate of syncytial nests of epithelioid-appearing cells that displayed no squamous or glandular differentiation, surrounded by a dense lymphocytic infiltrate. Results of immunophenotypic studies showed expression of high molecular weight cytokeratins and increased density of dermal dendrocytes within and adjacent to the tumor. No Epstein-Barr viral genomic sequences were detected by in situ hybridization, which suggests that cutaneous neoplasms may have different etiologic agents compared with similar tumors, found to be associated with this DNA-containing virus, arising in extracutaneous sites. The combined light microscopic and immunohistochemical assessment of this rate cutaneous neoplasm permits distinction of lymphoepitheliomalike carcinoma from benign/malignant lymphoproliferative disorders or neuroendocrine carcinomas.