Cutaneous manifestations of human papillomaviruses: a review

Human papillomaviruses (HPVs) are small DNA viruses of the papovavirus family, with more than 100 types already described. Their importance in human disease cannot be overemphasized because these agents are among the most common pathogens in cutaneous infectious diseases and are very important in a subset of predominantly, but not exclusively, genital squamous-cell carcinomas. HPVs can be associated with a variety of cutaneous as well as mucosal manifestations. Some types of HPVs are associated with increased risk of epithelial malignancies; these have been divided into low-risk and high-risk types based on their oncogenic potential. Clinical and histological features of HPV infection vary according to individual susceptibility (e.g., immunosuppressed patients), site of involvement, and type of HPV implicated. The histological features of HPV infection are very easy to identify on sections stained with hematoxylin and eosin. However, many findings usually associated with HPV infection are entirely non-specific. Additional current diagnostic methods for identification of HPV in tissues include techniques based on the detection of viral DNA; namely, in-situ hybridization and polymerase chain reaction (PCR). This article reviews the main clinical and histopathological cutaneous manifestations of HPV infection, including common warts, plantar warts, plane warts, condyloma acuminatum, Bowenoid papulosis, and epidermodysplasia verruciformis. Emphasis is placed on the clinical and histological features of these various manifestations, including a brief discussion about the routinely used laboratory methods for detecting HPV in tissues.