History: 50 year old male with chest pain.
A bulla is a thin-walled hole in the lung that must be larger than 10 mm. The hole contains no parenchyma, and there is a high contrast between the cavity and normal lung parenchyma.
Emphysema is classified typically as either paraseptal or centrilobular (although, another type is called panlobular emphysema). Paraseptal lucencies seen in emphysema are well-demarcated holes in the periphery of lung demarcated by thin-walled septa. Centrilobular lucencies are well-defined holes in the centrilobular portion of the secondary pulmonary lobule. Large apical predominant bulla are commonly seen in paraseptal emphysema.
Bullae are seen in multiple entities such as cocaine smoking, pulmonary sarcoidosis, alpha-1-antitrypsin deficiency, Marfan’s syndrome, Ehlers-Danlos syndrome and inhaled fiberglass exposure.