Epidermodysplasia verruciformis: viral particles in early malignant lesions.

Two cases of epidermodysplasia verruciformis were studied histologically and electron microscopically. Four lesions examined were histologically benign, and had viral particles morphologically similar to that of common human warts. Two lesions on the forehead and the face were histologically in the stages of malignant transformation, the intraepidermal epithelioma and the early invasive squamous cell carcinoma. Similar viral particles were also observed in the upper layers of these 2 lesions. These results suggest that at least some of the virus-induced lesions of epidermodysplasia verruciformis actually become malignant.