Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant skin disorder characterized by hyperkeratosis limited to the palms and soles and can be categorized into 2 types: Vörner and Unna-Thost types. The clinical expressions of the 2 types of EPPK are similar, but the histologic characteristics are different. Vörner type EPPK is characterized by vacuolar degeneration of keratinocytes in the upper spinous to granular layers. Unna-Thost EPPK can be distinguished from Vörner type because the Unna-Thost type lacks vacuolar degeneration.
Naoko Funakushi, Nobuyasu Mayuzumi, Ryohei Sugimura, Shigaku Ikeda. Epidermolytic Palmoplantar Keratoderma With Constriction Bands on Bilateral Fifth Toes. Arch Dermatol. 2009;145(5):609–610. doi:10.1001/archdermatol.2009.83