Birt-Hogg-Dubé syndrome with multiple cysts and recurrent pneumothorax: pathological findings.

A 39-year-old woman presented with right-sided pneumothorax. Partial lung resection was done via thoracoscopy. Five years later, left-sided pneumothorax occurred, and she underwent thoracoscopy again. However, air leakage continued, and pleurodesis was performed. Although she had no skin eruptions or renal tumors, Birt-Hogg-Dubé (BHD) syndrome was suggested by radiographic findings. BHD gene analysis was performed, which revealed the BHD gene mutation. Reevaluation of pathological findings showed elastic fibers in the alveolar walls with fine granular changes and accumulation of macrophages. BHD syndrome should be considered in patients presenting with multiple pulmonary cysts with or without skin eruption, or kidney tumor.