[Circumscribed acral hypokeratosis].

Circumscribed acral hypokeratosis is a rare chronic disorder of cornification that occurs predominantly in women. Lesions are solitary and do not respond to any local conservative treatment. They have to be differentiated by biopsy from other non-healing lesions and tumors in acral skin. Clinically lesions appear as sharply circumscribed reddish macules. The histologic hallmark is a circumscribed loss of the entire stratum corneum, which can be best demonstrated at the border of the lesion as a contrast to the perilesional broad stratum corneum typical for acral sites.