Porokeratosis palmaris et plantaris disseminata: an unusual clinical presentation.

A 54-year-old man and his son had porokeratoses of the trunk and extremities, predominantly on the palms and soles. Numerous small, slightly depressed, opalescent rings with hyperemic borders were present on the oral mucosa. The spectrum of porokeratosis palmaris et plantaris disseminata and the differential diagnosis of other types of porokeratosis are discussed.