Background: Squamous cell carcinoma (SCC) of the nail unit, known as the subungual region, and of the plantar foot is rare but often misdiagnosed due to its similar appearance to verruca, a common wart. The delayed diagnosis and treatment of SCC in the subungual and plantar foot leads to poorer outcomes. Human papillomavirus (HPV), and specifically the oncogenic potential of particular strains, influences SCC pathogenesis, progression, and treatment response. Methods: This review aims to address the current state of knowledge as well as deficits associated with clinical treatment of SCC in two anatomically challenging locations: verrucous carcinoma (VC), a variant of SCC that affects the plantar foot, and subungual SCC. Articles reviewed were evaluated based on date of publication, quality, and originality. Additionally, articles published after 2015 were given preferential consideration. Results: This review highlights considerations to reduce diagnostic delays and improve patient outcomes when considering two uncommon cutaneous malignancies. Conclusions: We recognize that misdiagnosis poses a barrier in the treatment of both plantar VC and subungual SCC. As such, we identify pertinent clinical pearls to assist in accurate identification and treatment of SCC in these locations. Lastly, we address the role of HPV and the microbiome in the pathogenesis of SCC to improve treatment efficacy.
Moraga et al. (Tue,) studied this question.