Transformation of common warts into squamous cell carcinoma on sun-exposed areas in an immunosuppressed patient.

We report one case of renal transplant recipient who developed widespread multiple verrucous skin lesions. Histologic examination revealed typical warts and, only from several sites exposed to sun (hands and face), a development of dysplasia within the warts and a transformation of some of them toward infiltrating squamous cell carcinoma (SCC). Human papillomavirus (HPV) testing for DNA by polymerase chain reaction DNA amplification identified HPV type 1 in both warts and SCC. Our findings suggest that classic warts may progress to high-grade lesions and that, in addition to the oncogenic potential of the virus alone, other factors including the host's immunosuppressed state and ultraviolet radiation seem to be essential to malignant transformation.