Pneumatocele

A pneumatocele is a cavity in the lung parenchyma filled with air that may result from pulmonary trauma during mechanical ventilation.

[5] A pneumatocele can become enlarged, for example when the patient is mechanically ventilated or has acute respiratory distress syndrome, in which case it may not go away for months.

[6] Diagnosis can be made using chest X-ray; the lesion shows up as a small, round area filled with air.

[1] Differential diagnoses – other conditions that could cause similar symptoms as pneumatocele include lung cancer, tuberculosis,[7] and a lung abscess[1] in the setting of hyper IgE syndrome (aka Job's syndrome), as a complication of COVID-19 pneumonitis,[8] or on its own, often caused by Staphylococcus aureus infection during cystic fibrosis.

"Incidental Intraosseous Pneumatocyst with gas-density-fluid level in an adolescent: a case report and review of the literature".