Secondary pneumothorax associated with Birt-Hogg-Dubé syndrome: a case report.

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal-dominant inherited disease. Typical clinical features include skin lesions, pulmonary cysts, and renal tumors. However, the syndrome remains to be underdiagnosed as a result of its heterogeneous clinical manifestation. In this report, we present the case of a 75-year-old male patient who was referred to the emergency department with pneumothorax, leading to the diagnosis of BHDS. Based on characteristic morphologic features, radiologists have the opportunity to propose BHDS as a differential diagnosis. Establishing the diagnosis in a timely manner is crucial, as these patients require lifelong screening examinations for renal cancer.