Warty papule and scaling around finger

Dx: Bowen’s disease of the nail

Bowen’s disease (BD), a form of intraepidermal (in situ) squamous cell carcinoma (SCC), may affect the skin but also the nail unit. It presents as periungual or subungual verrucous plaques, erosions, and ulcerations, with nail discoloration, dystrophy, or onycholysis.

Our patient was younger than the norm. BD of the nail—which typically involves the fingers—occurs in both men and women, but is most common in men in their 50s. It often presents with verrucous, scaly, crusting, erythematous, or fissuring lesions that may involve any portion of the nail apparatus with associated onycholysis, nail dystrophy, or longitudinal erythronychia or melanonychia (red or black longitudinal nail streak).^1-6 BD of the nail may involve more than one digit on multiple extremities, simultaneously or sequentially.⁵ Initial BD of the nail may spread to periungual or subungual areas or vice versa. Bleeding, ulceration, or a nodule may signal the development of invasive SCC.^3,6

Radiation and HPV linked to BD of the nail

While the etiology of this condition is unclear, trauma, chronic paronychia, ionizing radiation, infectious agents, ultraviolet exposure, arsenic or pesticide exposure, and immunosuppression are a few proposed predisposing factors.^1,3,4,6

Human papilloma virus (HPV) subtypes 16, 34, and 35 have been identified in BD and SCC lesions. These subtypes with oncogenic potential may play a role in the development of BD and invasive SCC of the nail and other cutaneous regions.

In cases where there has been HPV-16 infection in a digit and the genital region, researchers have suggested autoinoculation as a transmission mode from the anogenital area to the digit, or vice versa.^6-8

The pathogenesis behind polydactylous BD of the nail has been linked to factors such as trauma, radiation, and immunosuppression (eg, post-transplant, oncological, and HIV patients).^5,8