Co-existence of variants of porokeratosis: a case report and a review of the literature.

Rarely, different variants of porokeratosis may coexist in an individual patient or their family members. A patient with the linear form of porokeratosis present since birth subsequently developed the disseminated superficial actinic form at a later age. A review of the literature pertaining to the coexistence of variants of porokeratosis suggests a significant association between the linear and disseminated superficial actinic forms. Genetic linkage between different variants and the basis for their association is discussed.