Bowen Disease Within a Circumscribed Palmar Hypokeratosis.

Circumscribed palmar or plantar hypokeratosis is a focal disorder of keratinization that consists of a reduction in the thickness of the corneal layer of the epidermis of palms or soles. Although it is considered a benign entity, the thinning of the stratum corneum facilitates ultraviolet damage in the affected skin, which may result in an increased risk of developing focal epidermal dysplasia. Other factors, such as immunosuppression in transplanted patients, may play a role as well. We present a case of circumscribed palmar or plantar hypokeratosis with features of Bowen disease limited to the hypokeratotic epidermis.