Birt-Hogg-Dubé syndrome presenting with macroscopic pulmonary cyst formation in a 15-year-old.

Birt-Hogg-Dubé (BHD) syndrome is a rare, autosomal dominant disorder caused by a germline mutation in the folliculin gene (17p11.2). It is characterized by benign skin lesions, renal tumours, and pulmonary cysts, with pneumothoraces seen exceptionally rarely in patients younger than 40 years. We report the case of a 15-year-old boy who presented with sudden onset left-sided chest pain and acute dyspnoea secondary to a large left-sided pneumothorax. This failed to resolve despite chest drain insertion and he required video-assisted thoracoscopic surgical pleurodesis, which revealed macroscopic pulmonary cyst formation. Following this, he made a good recovery and a further high-resolution computerized tomography (CT) scan of his chest identified multiple, small, subpleural parenchymal lung cysts that were not initially visible on prior imaging. Further questioning revealed a strong family history of spontaneous pneumothoraces and additional genomic sequencing, and confirmed a diagnosis of BHD syndrome. We highlight the diagnostic, management, and surveillance challenges for this rare syndrome.