Epidermal hamartoma presenting as longitudinal pachyleukonychia: a new nail genodermatosis.

Abstract

Epidermal hamartomas involving the nail apparatus are uncommon. Our purpose was to define the clinical, genetic, and histologic features of a unique nail abnormality. We examined eight members of three generations who presented with an unusual nail abnormality, longitudinal pachyleukonychia, as a sole characteristic that appeared between the ages of 9 and 30 years. One nail was examined histologically. Histologic examination showed pronounced hyperplasia of the nail bed with papillomatosis. Cell nests of a sebaceous type were included in the epithelial digitations. This dysplasia was not accompanied by abnormalities affecting skin, hair, teeth, or sweat glands. This unique epidermal hamartoma appears to be inherited as an autosomal dominant condition.