SummarySquamous cell carcinoma (SCC) of the nail unit is a rare disorder. An association with high-risk genital human papillomavirus (HPV) infection has been reported. We report a 28-year-old human immunodeficiency virus (HIV)-infected bisexual man who had multiple invasive SCC of the fingers, infected with the rare type HPV 26. Classification of HPV 26 as high-or intermediate-risk type has been uncertain, due to its rare presence in cervical cancer. Despite successful treatment with highly active antiretroviral therapy (HAART), the patient developed extensive hyperkeratotic nailbed proliferations of all fingers. Tumours were refractory to treatment and invaded into adjacent tissues. X-rays of the hands demonstrated bone invasion, necessitating amputation of distal phalanges of several fingers. Histologically, highly differentiated preinvasive and invasive verrucous SCCs were identified. Molecular DNA typing identified HPV 26 in the SCCs and in some premalignant lesions. By in situ hybridization HPV 26 DNA was detected in numerous tumour cells, indicating productive infection with high-level amplification of the viral genome. In the remaining proliferations, high-risk HPV type 58, cutaneous HPVs and a putative new HPV type were identified. HPV 26 infection appears to be causally involved in the development of SCC of the nail unit in this immunosuppressed patient. Timely evaluation of chronic verrucous nailbed tumours is recommended, especially in immunocompromised patients. Identification of HPV 26, besides known high-risk HPV types, may identify patients at risk for developing SCC of the nailbed and possibly at other locations. especially on sun-exposed areas, whereas a possible role of HPV in keratinocyte (nonmelanoma) skin cancer of immunocompetent and immunosuppressed individuals is less clear. [4][5][6] SCC originating from the nail unit is rare, and misdiagnosis as onychomycosis or verruca vulgaris is quite common. SCC of the finger usually affects older age groups, and men more often than women. 7,8 An association with preceding radiation, chronic trauma or infection, immunosuppression, and exposure to hydrocarbons or arsenic has been reported. 8,9 Infection with high-risk HPV has been causally implicated in the pathogenesis of digital SCC, and the predominant type identified was HPV 16, suggesting that its high oncogenicity largely accounts for it being the main HPV type identified in most cases (similar to cervical cancer).
KeywordsTo a lesser extent HPV 31, 33 (our unpublished observation), 34 and 35 have been identified, all closely related phylogenetically to HPV 16, as all are species 9 alphapapillomavirus 1,7 or species 11 alpha-papillomavirus. 10 Digital SCCs have been reported in patients with concomitant or antecedent genital HPV infection, and a proportion associated with cervical cancer, but most with genital warts or cervical dysplasia. The presence of the same HPV type in the digital and genital lesions has been identified. 8
Case reportA 28-year-old human immunodeficiency virus (HIV)-infect...