Radiologically indeterminate pulmonary cysts in Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé (BHD) syndrome is an inherited disease characterized by recurrent pneumothorax. We report some unusual clinicopathologic features of the lung in a Japanese family with this syndrome presenting with recurrent pneumothorax. Radiologic imaging did not show detectable lesions; however, at video-assisted thoracic surgery (VATS), multiple diffusely distributed microcysts were visible on the pleura. This characteristic morphologic feature was common to all affected family members. The proband underwent genetic testing and BHD syndrome was diagnosed. Although many patients with BHD syndrome with pneumothorax show obvious pulmonary cysts, this case suggests that radiologically indeterminate cysts have the potential to cause pneumothorax.