Pulmonary cysts

Thin-walled (≤2 mm), air-filled parenchymal lucencies on CT with a well-defined interface with adjacent normal lung, distinct from cavities, emphysema, and bronchiectasis, representing localized or diffuse structural abnormalities of the lung parenchyma.

Causes

• Smoking-related causes

  • Cigarette smoking

  • Pulmonary Langerhans cell histiocytosis

• Genetic and inherited causes

  • Birt–Hogg–Dubé syndrome

  • Tuberous sclerosis

  • Lymphangioleiomyomatosis

• Infectious and inflammatory causes

  • Pneumonia

  • Lung abscess

  • Post-infectious lung changes