Cystic lung disease in Birt-Hogg-Dubé syndrome. A case series.

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant inherited disease caused by mutations in the folliculin (FLCN) gene. It is characterized by lung cysts, skin fibrofolliculomas and an increased risk for the development of renal cancer, especially chromophobe. Lung cysts in the context of BHDS are typically lower lobe predominant, paramediastinal, in relation to the fissures and often elliptical shaped. Skin manifestations can easily go unnoticed. Respiratory physicians need to have a high degree of vigilance as they can be the first to suspect the disease in the setting of diffuse cystic lung disease. Meticulous skin examination and referral to a dermatologist is of utmost importance as it can establish the diagnosis in the least invasive way. Correct diagnosis is crucial as it may allow for genetic counseling to the affected family and the implementation of a monitoring strategy for early detection of renal cancer.