[Facial papules and pneumothoraces. Birt-Hogg-Dubé syndrome].

A 43-year-old man presented with white to skin-colored shiny papules on the face and neck. In addition, he had a positive family history and reported on multiple pneumothoraces. Histopathological examination revealed a papular mucinosis. Considering these findings, we made the diagnosis of Birt-Hogg-Dubé syndrome (BHDS) that was confirmed by molecular genetic analysis. This autosomal dominantly inherited tumor disorder is caused by germline mutations in the folliculin (FLCN) gene that encodes for the eponymous protein folliculin. Clinically, BHDS is predominantly characterized by the occurrence of fibrofolliculomas and trichodiscomas. A papular mucinosis, as encountered in our patient, has been described only once previously. Besides the cutaneous symptoms the disease can be associated with lung cysts and pneumothoraces as well as the development of benign and malignant kidney tumors. Following confirmation of BHDS on the DNA level, all patients with multiple cutaneous fibrofolliculomas should be treated in an interdisciplinary setting and undergo regular prophylactic screening examinations due to the association with renal cell carcinomas.