The Birt-Hogg-Dubé syndrome is characterized: a) clinically, by an asymptomatic eruption of dome-shaped papules involving the head, neck, chest, back and arms frequently associated with acrochordons; b) histologically, by multiple follicular tumors, namely fibrofolliculomas and trichodiscomas, representing benign proliferations of mesodermal and ectodermal components of the pilar apparatus; c) by the apparent autosomal dominant mode of inheritance. This study is concerned with two families whose various members belonging to two and three generations have the clinical and histological lesions of this syndrome. In several biopsies performed, the main finding was the fibrofolliculoma isolated or associated with perifollicular fibromas; in five biopsies, was noted a typical trichodiscoma associated, in two of them, with a perifollicular fibroma. Clinically, the fibrofolliculomas were indistinguishable from trichodiscomas. We believe that the Birt-Hogg-Dubé syndrome is an autonomous well individualized skin disease. Its existence supports the view of the close interaction between the epithelial and mesodermal components of the pilar complex.