A Japanese family with multiple lung cysts and recurrent pneumothorax: a possibility of Birt-Hogg-Dubé syndrome.

We herein report a Japanese family lineage, possibly demonstrating Birt-Hogg-Dubé (BHD) syndrome. A 29-year-old nonsmoking woman was admitted to our hospital due to spontaneous pneumothorax. A chest CT showed multiple lung cysts, and breast cancer was simultaneously detected that needed priority surgical treatment. In the family history, the patient's father and half brother also experienced recurrent pneumothorax, and both had similar findings in their chest CT. In a genetic analysis of her half brother, the mutation of the BHD gene was identified. BHD syndrome is a rare autosomal and dominantly inherited disorder, which has three characteristics: multiple lung cysts that may be associated with pneumothorax, skin fibrofolliculomas, and renal neoplasm. For multiple-cystic disease of the lungs with an unknown etiology, or pneumothorax, as seen in a family history, it is necessary to consider the possibility of BHD syndrome.