Dowling-Degos disease: case report and review of the literature.

Dowling-Degos disease (DDD) is an unusual pigmentary disorder usually caused by mutations in keratin 5. A 44-year-old woman in good general health presented due to the recent appearance of numerous pigmented macules on her axillary and anogenital skin. A biopsy showed lacy, finger-like epidermal extensions into the dermis which were heavily pigmented and associated with tiny cysts or dilated follicles. We view DDD as part of a spectrum of disorders which are morphologically related but vary in location and time of expression. In addition, both the clinical and histological differential diagnostic considerations are extensive.