Lymphoepithelioma-like carcinoma of the skin: a report of 3 Epstein-Barr virus (EBV)-negative additional cases. Immunohistochemical study of the stroma reaction.

Lymphoepithelial carcinoma is a relatively common malignancy in the nasopharynx, but it rarely occurs in other sites. We report 3 additional cases of cutaneous location. Histopathologically, the tumors consisted of multiple well-circumscribed dermal-hypodermal nodules composed of aggregates of undifferentiated malignant cells. These cells had moderate amounts of eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli. There was no squamous or glandular differentiation. For each case, a heavy lymphoplasmacytic infiltrate was found. No dysplasia was noted in the epidermis. In one case, the tumoral component showed numerous Sternberg-like cells scattered within a lymphocytic background. This case might be mistaken with a Hodgkin's lymphoma. Immunohistochemistry showed that the neoplastic cells were positive for cytokeratin and epithelial membrane antigen. In the present report, studying the stroma reaction cell components, we have stressed the presence of numerous factor XIIIa-positive dendritic cells in 2 cases. Because of the role of these cells in the immune response of normal stroma, their presence herein might be in relation with the favorable prognosis of this type of primary skin carcinoma. No Epstein-Barr viral genomic sequences were detected by in situ hybridization. This negativity for Epstein-Barr virus may be a help in the differential diagnosis from metastatic undifferentiated nasopharyngeal carcinoma.