Digital squamous cell carcinoma and association with diverse high-risk human papillomavirus types

Digital squamous cell carcinoma (SCC) presents a diagnostic challenge because of its relatively rare occurrence and mimicry of benign conditions. Although low-risk human papillomavirus (HPV) subtypes are commonly associated with benign digital verrucae, digital SCC can be associated with high-risk, oncogenic HPV subtypes. We report 7 patients, including 4 HIV-positive patients, who presented with 10 lesions of digital SCC in situ. Six of 10 lesions were typed for HPV by immunostain or polymerase chain reaction. Multiple high-risk oncogenic subtypes were found, including HPV-16, -33, -51, and -73. The majority of reports linking HPV and digital SCCs have implicated the HPV-16 subtype. This case series highlights the diversity of oncogenic HPV types that may be associated with digital SCCs. Because the high rate of recurrence of digital SCCs may be a result of persistence of oncogenic HPV at the margins of resection, aggressive treatment of individual lesions and of genital reservoirs for HPV on patients and their sexual partners is warranted. (J Am Acad Dermatol 2011;64:981-5.)