Verrucous skin lesions have been attributed to various herpes viruses in immunosuppressed patients, including those with human immunodeficiency virus infection (HIV). We examined such lesions from six HIV-infected patients to determine the range of microscopic findings present and to establish which herpesviruses were present. Verrucous epidermal hyperplasia. pseudocarcinomatous hyperplasia, and massive hyperkeratosis correlate with the warty clinical appearance of the lesions. Herpetic cytopathic changes, including multinucleated epidermal giant cells, steel-gray nuclei, necrotic acantholytic keratinocytes, and Cowdry type A nuclear inclusions were seen most prominently in the dells between papillations and in adnexal epithelium. In two cases, increased numbers of spindled cells were seen in the dermis. Immunoperoxidase staining with anti-type IV collagen antibodies demonstrated that these findings were not those of Kaposi's sarcoma, but represent a fibrotic reaction to the infection. Viral cultures of four of the cases demonstrated the presence of varicella-zoster virus, whose presence was detected by the polymerase chain reaction in paraffin-embedded lesional tissue from all six cases. Polymerase chain reaction did not show the presence of cytomegalovirus. herpes simplex, Epstein-Barr, or human papillomavirus. We conclude that these unusual verrucous lesions are a chronic manifestation of herpes zoster infection and that the reported presence of other agents in such lesions is probably coincidental.