ABSTRACT
Most cases of nonpigmented subungual malignant neoplasias correspond to SCC, of which the maximum incidence is at between 50 and 70 years. Men are more frequently affected. It is mainly due to oncogenic human papilloma virus (HPV). HPV 16 subtype is identified in most cases of HPV-associated SCC of the nail apparatus, suggesting a genital-digital transmission.7 The evolution is mostly slow, but the tumor can rarely adopt a locally aggressive behavior
leading to amputation. Metastases are exceptional regardless of the immune status.7 It is monodactylic in most cases and mainly affects the nail bed or the paronychium. The former localization is responsible for its most usual clinical presentation, associating onycholysis and subungual hyperkeratosis or a verrucous aspect. In the latter case, a hyperkeratotic or verrucous aspect can affect the periungual folds. However, nail SCC can mimic various benign conditions such as benign tumors (onychomatricoma, epidermoid cyst, fibrokeratoma, exostosis) or infectious conditions (warts, bacterial paronychia, onychomycosis).1 In most typical cases, dermoscopic examination of the nail plate reveals longitudinal leuko-xanthonychia with, in few cases, areas of grayish coloration. Splinter hemorrhages are also seldom seen. A localized (distally to the longitudinal abnormalities) subungual hyperkeratosis at the nail plate free-edge dermoscopic examination is a key criterion for all nail matrix keratinizing tumors.8
