Pulmonary bulla

Last revised by Liz Silverstone on 6 Mar 2024

A pulmonary bulla (pleural bullae) is a gas-containing cystic structure formed by confluent destroyed and dilated airspaces (distal to terminal brochioles). They are typically well-demarcated and rounded with a fine smooth lining composed of a thin layer of collapsed lung 6.

Although bullae are typically larger than blebs, there is no defining size limit for either in the 2024 Fleischner glossary 6.

They are often subpleural in location and are typically larger in the apices. In some cases, bullae can be very large and result in compression of adjacent lung tissue. A giant bulla is arbitrarily defined as one that occupies at least one third of the volume of a hemithorax 5. When large, bullae can simulate pneumothorax.

The most common cause is paraseptal emphysema but bullae may also be seen in association with centrilobular emphysema.

Location-specific subtypes


See also

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