Dowling-Degos disease: classic clinical and histopathological presentation.

Dowling-Degos disease (DDD) is a rare genetic disease of the skin (reticulate pigmented anomaly), clinically characterized by flexural brown pigmented reticulate macules, comedo-like papules on the back, neck and pitted perioral or facial scars. We present the case of a 51 year-old man with macrocomedo-like lesions, pitted scars, cysts, hyperpigmented macules in his back, chest, axillae, neck, groin and face. The patient reported having two children, three brothers and a father with a similar condition. The histopathology of the skin biopsies was very characteristic of Dowling-Degos disease, showing dilated follicular, fingerlike projections called rete ridges (dermal pegs), with thinning of the suprapapillary plates, resulting in an "antler-like" pattern and increased pigmentation of the basal layer.