Lymphoepithelioma-like carcinoma of the skin with spindle cell differentiation

Primary cutaneous LELC is a cutaneous neoplasm with histopathologic features identical to those seen in the undifferentiated subtype of nasopharyngeal carcinoma. It is extremely rare, with only approximately 30 cases reported in the literature.

We report a case of primary cutaneous LELC arising on the forehead of a 72 year-old male in which a proportion of the neoplastic cells demonstrated distinctive spindle cell morphology.

Microscopic examination showed a dense lymphoplasmacytic infiltrate admixed with large spindle-shaped cells with vesicular nuclei, prominent nucleoli, and frequent mitotic figures. These cells were negative for an extensive panel of immunohistochemical markers and positive only for broad-spectrum cytokeratins and epithelial membrane antigen. There was no connection between the tumor and the epidermis and no epidermal dysplasia. In situ hybridization for Epstein-Barr virus was negative.

The spindle cell differentiation in this case is unusual and suggests that in some cases the differential diagnosis of cutaneous spindle cell neoplasms might include primary cutaneous LELC.