Squamous cell carcinoma arising in pemphigus vulgaris during immunosuppressive therapy

A rapidly growing squamous cell carcinoma developed in an area of active pemphigus vulgaris on the cheek of a 45-year-old woman during treatment with prednisone and cyclophosphamide. This is the first reported case of this phenomenon. The roles of solar and drug carcinogenesis, autoimmunity, and immunosuppression in the pathogenesis of this tumor are discussed.