Pulmonary cavities

Pulmonary cavities are thick-walled abnormal gas-filled spaces within the lung. They are usually associated with a nodule, mass, or area of consolidation. A fluid level within the space may be present. Plain radiography and CT form the mainstay of imaging.

Terminology

According to the Fleischner Society, pulmonary cavities are defined as "a gas-filled space, seen as a lucency or low-attenuation area, within pulmonary consolidation, a mass, or a nodule" ⁷.

Pathology

The cause of pulmonary cavities is broad. They may develop as a chronic complication of a pulmonary cyst or secondary to cystic degeneration of a pulmonary mass. They may enlarge or involute over time.

Etiology

Pulmonary cavities may be the result of malignancy, infection, inflammation, or be congenital:

• cavitating malignancy
  • primary bronchogenic carcinoma (especially squamous cell carcinoma)
  • cavitating pulmonary metastases
    • squamous cell carcinoma
    • adenocarcinoma, e.g. gastrointestinal tract, breast
    • sarcoma
• infection
  • pulmonary tuberculosis ³
  • pulmonary bacterial abscess/cavitating pneumonia
  • post-pneumonic pneumatocele: a thin walled pneumatocele is not really a cavity but when infected can be thick-walled
  • septic pulmonary emboli
  • other rare infections
    • pulmonary coccidioidomycosis
    • pulmonary actinomycosis / thoracic actinomycosis
    • pulmonary nocardiosis
    • melioidosis
    • pulmonary cryptococcosis ⁸
• non-infective granuloma
  • granulomatosis with polyangiitis
  • rheumatoid nodules
• vascular
  • pulmonary infarct
• trauma
  • pneumatoceles (a thin-walled pneumatocele is not really a cavity)
• congenital (not true "cavity")
  • congenital cystic adenomatoid malformation (CCAM)
  • pulmonary sequestration
  • bronchogenic cyst

A helpful mnemonic is CAVITY. 

See also

• pulmonary mass
• pulmonary cyst 
• pulmonary cavity
  • pulmonary cavity (mnemonic)
• pulmonary nodule