An unusual wart-like skin lesion found in a renal allograft recipient.

Immunosuppressed renal allograft recipients have an increased tendency to acquire warts. While studying such patients, we found a virus-induced, wart-like lesion that had an unusual histologic picture. Light microscopic studies showed bizarre keratinocytes with cytoplasmic, juxtanuclear, giant, crescentic bodies and round, nuclear inclusions, By electron microscopy, the giant cytoplasmic bodies were found to be composed of tonofilaments, and the nuclear inclusions were found to be composed of papillomavirus-like particles in a filamentous matrix. Typical papillomavirus particles were observed in a wart extract by the negative-staining method. Although virus was abundant in infected cells, no structural viral antigens of the human papillomavirus (HPV) types 1, 2, 3, or 5 could be detected by immunofluorescence microscopy, indicating infection by HPV 4 or some other, as yet undescribed, HPV type.