A case of multiple cutaneous carcinomas arising from psoriasis vulgaris during its clinical course

A 54-year-old man was diagnosed to have psoriasis vulgaris in 1956. He had been treated by Goeckerman therapy in 1970 and 1972. Although he did not undergo any further phototherapy, several skin tumors developed which were diagnosed to be Bowen's disease and basal cell carcinoma (BCC) also appeared on his legs in 1985. Skin tumors diagnosed as Bowen's disease and BCC later appeared one after another on his legs, arms, face and scalp. In 2001, another nodule appeared in his preauricular region which was histopathologically diagnosed to be squamous cell carcinoma (SCC). The patient had not undergone any radiotherapy or any treatment with an arsenic compound or cyclosporine during the clinical course of psoriasis vulgaris. Possible risk factors for the skin carcinomas were Goeckerman therapy and daily exposure to sunlight (because he had been jogging outside for long periods of time for more than 25 years). Since most of his skin carcinomas appeared on the exposed parts of his body, we concluded that not only Goeckerman therapy but also exposure to natural ultraviolet light caused the multiple carcinomas in this case.