Human Papillomavirus in Bowen Disease: Site-Specific Prevalence, Genotype Distribution, and Clinical Implications...

Bowen disease (BD), or squamous cell carcinoma (SCC) in situ, represents a histologically defined but biologically heterogeneous group of intraepithelial neoplasms arising across different epithelial compartments. Human papillomavirus (HPV) plays a well-established causal role in anogenital squamous intraepithelial neoplasia, whereas its contribution to extragenital BD, including nail apparatus and general cutaneous lesions, has remained controversial. We performed a narrative review of the literature to synthesize current evidence on HPV prevalence, genotype distribution, and pathogenetic relevance in BD across three anatomical sites: nail apparatus, general cutaneous skin, and anogenital region. Available data reveal a clear site-dependent gradient of HPV involvement. Anogenital BD is overwhelmingly driven by high-risk α-HPV genotypes and shares molecular hallmarks of HPV-mediated carcinogenesis. Nail apparatus BD shows a consistently high prevalence of transforming α-HPV types, suggesting a biologically distinct subset of extragenital disease. In contrast, general cutaneous BD demonstrates highly variable HPV detection, predominantly involving β- and occasionally γ-HPV types, with evidence supporting a permissive or incidental rather than causal role. These findings indicate that BD should not be regarded as a unified viral neoplasm but as a convergent histologic phenotype arising from distinct pathogenetic pathways. Anatomical context is therefore essential for interpreting HPV detection and its diagnostic and clinical implications.