Histopathology of skin lesions in renal allograft recipients--an assessment of viral features and dysplasia.

We report the pathology of benign and malignant skin lesions from 13 renal allograft recipients. The 59 lesions included 18 squamous carcinomas, 16 verrucous keratoses, 19 warts with varying dysplasia, three plaque lesions resembling those found in epidermodysplasia verruciformis, two non-specific keratoses and one basal cell carcinoma. We delineate criteria for histological assessment of the presence of human papilloma virus (HPV) and use the term verrucous keratosis for lesions in which there is a putative viral contribution. Our findings emphasize the lack of correlation between clinical and histological assessment of the lesions. We note the variable and significant dysplasia within otherwise typical viral warts and the architectural features suggestive of HPV presence in the dysplastic lesions and in in situ and invasive squamous carcinomas. Parallel virological studies have revealed the presence of HPV 5/8 in over 60% of the invasive and in situ carcinomas probed. These HPV types have previously been isolated from squamous carcinomas of epidermodysplasia verruciformis, a condition whose defective cell-mediated immunity may be compared with that of the immunosuppression in our patients.