Subungual squamous cell carcinoma: report of five cases and its importance in the differential diagnosis of nail lesions

Subungual squamous cell carcinoma is a rare condition, and its diagnosis is often late. The clinical presentation is atypical and simulates other benign conditions, such as verruca vulgaris, onychomycosis and trauma-induced nail dystrophy. Although it is an unusual entity, we should be attentive to its early diagnosis, considering the biopsy in the chronic nail lesions refractory to treatments. We present five cases of subungual squamous cell carcinoma, in which pain was the most prevalent symptom, and their possible association with trauma and HPV infection should be considered.