Subungual epidermoid inclusions: report of 8 cases

Eight cases of subungual epidermoid cysts associated with distinctive nail abnormalities are reported. Toes and thumbs were the most frequent sites affected by this probably not rare condition. The most striking clinical features were subungual hyperkeratosis associated with shortened and dystrophic nail plate. A history of trauma was frequent. In all cases, the nail biopsy showed marked hyperplasia of the nail bed and epidermoid cysts in the dermis. The authors propose a new classification for subungual epidermoid cysts.