Pulmonary cyst

Last revised by Dr Yuranga Weerakkody on 21 Feb 2021

Pulmonary cysts are round, thin-walled, low attenuation spaces/lucencies in the lung. Lung cysts usually contain air but occasionally also contain fluid or solid material 5.

In contradistinction to all other organs, the term cyst as used in the lung is a misnomer, as it usually refers to a contained focus of gas, not fluid.

Pulmonary cysts can be congenital or acquired. Multiple lung cysts in a child may be associated with an underlying process although this is rare, e.g. pleuropulmonary blastomas 1.

There are several specific types of thin-walled cystic spaces in the lungs 6,7:

  • bleb: pleural/subpleural, ≤1-2 cm diameter
  • bulla: pleural/subpleural, ≥1-2 cm diameter
  • honeycombing: subpleural stacks of cysts, typically 3-10 mm diameter with walls 1-3 mm in thickness
  • pneumatocele: usually transient cystic airspace within the lung, usually due to pneumonia or trauma

There are several mimics of pulmonary cysts:

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Cases and figures

  • Case 1
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