Punctate follicular porokeratosis: clinical and pathologic features

Porokeratosis is a disorder of keratinization characterized by an abnormal cornoid lamella surrounding an annular, scaly plaque with an atrophic center. A histologic variant of this condition has been proposed, termed follicular porokeratosis, in cases where follicular involvement was contiguous with an annular cornoid lamella. There has been only 1 report of punctate follicular porokeratosis, in which cornoid lamellae originated exclusively from hair follicles with no associated annular plaque. The authors present the second case of punctate follicular porokeratosis, further supporting the contention that this entity is a unique form of porokeratosis rather than a histologic variant. A 56-year-old African American female presented to the dermatology clinic with a 3-month history of keratotic lesions localized on the right posterior shoulder. Examination revealed an area of perifollicular keratotic papules, each surrounded by an erythematous rim. Histopathology revealed a cornoid lamella originating within a hair follicle, with the parakeratotic column protruding through the follicular orifice. The static nature of the condition along with exclusive involvement of hair follicles supports the notion of punctate follicular porokeratosis as a distinct clinical entity. The diagnosis of this condition relies heavily on proper histopathologic sampling revealing punctate follicular cornoid lamellae.