Porokeratosis plantaris palmaris et disseminata.

Porokeratosis plantaris palmaris et disseminata (PPPD) is a rare variant of porokeratosis. We report a second kinship with PPPD that typically appears first on the palms and soles and then gradually progresses to the extremities and trunk. We discuss clinical, histologic, pathogenetic, and therapeutic aspects of PPPD and review the literature concerning the histogenesis of cornoid lamella formation.