Lymphoepithelioma-like carcinoma of the skin with potential for sweat glandular differentiation

Lymphoepithelioma-like carcinoma of the skin (LELCS) is a cutaneous malignancy with histopathological resemblance to lymphoepithelioma of the nasopharynx. Its histogenesis remains unknown, and few cases showing skin appendage differentiation have been reported to date. We present the case of a 77-year-old Japanese male with an asymptomatic red nodule on his left cheek. Because the histopathological study revealed focal growth of tumor cells lacking connections with the epidermis and marked lymphocytic infiltration surrounding the neoplastic cell nests, the case was diagnosed as LELCS. On immunohistological staining, the neoplastic cells were positive for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), multi-cytokeratin (CK), CK6, CK18, and CK19. On the basis of these results, we suggested that skin appendage differentiation, particularly sweat glandular differentiation, was present in this case.