Painful subungual keratotic tumors in incontinentia pigmenti.

We report a case of dyskeratotic subungual tumor in a 28-year-old woman. The patient presented achromic lineal lesions, typical of residual incontinentia pigmenti (IP), on her legs. Furthermore, the physical examination showed anodontia of the right incisor tooth. The familial background demonstrated miscarriages of male fetuses and characteristic dental abnormalities of IP in female siblings. The patient's daughter presented a typical background of IP and dyschromic splashed lesions. Light and electron microscopic studies of the subungual tumors were made. The analogy between subungual tumors of IP and keratoacanthoma is emphasized.