Subungual keratoacanthoma: a variant of verrucous squamous cell carcinoma of the skin.

A case of so-called subungual keratoacanthoma is reported. Clinically and morphologically, this lesion is similar to a verrucous carcinoma of the skin. It is possible that subungual keratoacanthoma and carcinoma cuniculatum (verrucous carcinoma) are different aspects of the same entity.