Pulmonary bullae

Focal, thin-walled, air-filled cavities within the lung parenchyma, usually >1 cm in diameter, resulting from emphysematous destruction of alveolar walls and associated with localized loss of gas-exchange surface and potential compression of adjacent lung. Possibel causes are cigarette smoking, cannabis smoking, crack cocaine, α-1 antitrypsin deficiency, Marfan syndrome, Ehlers-Danlos syndrome, sarcoidosis, Sjögren's disease, HIV/AIDS or severe pneumonia.