Pulmonary cyst

Last revised by Dr Rishabh Verma on 07 Oct 2022

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.

They are generally seen in patients <40 years of age and are associated with a low BMI 9.

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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