[Dowling-Degos disease with exclusively genital manifestations]

We report on two women with pigmented lesions of the vulva. The histopathology (filiform downgrowth of pigmented epithelial strands two to four cells wide, extending from the interfollicular epidermis and from follicular infundibula; no increased numbers of melanocytes; horn pseudocysts) was specific for Dowling-Degos disease. One patient also had acne inversa, and the other patient had been treated surgically for a pilonidal sinus some years before. The spectrum of conditions that should be considered in the differential diagnosis of genital pigmented lesions is discussed. Vulvar melanosis, genital lentigo, malignant melanoma, acanthosis nigricans maligna and benigna and syndromes occurring concomitantly with pigmentation of the mucosa need to be excluded. The association of Dowling-Degos disease with acne inversa, which was recently described for the first time, is discussed.