Radiological criteria

Hole in lung with a wall, lumen and contents. Focus of increased density whose central portion has been replaced by air.

Following characteristics help in differential diagnosis.


Multiple bilateral cavities would raise suspicion for either bronchogenous or hematogenous process. You should consider

            Single cavity


A large cavity encompassing the entire lobe or lung should raise suspicion for gangrene of lung.


Wall Thickness

Lining of wall

The lining of wall is irregular and nodular in cancer lung or shaggy in lung abscess  . The appearance is akin to stalactites and stalagmites.


Associated Features

Ipsilateral lymph nodes or lytic lesions of bone is seen with malignancy.

Evolution of lesion

Many times review of old films to assess the evolution of the radiological appearance of the lesion extremely helpful. Examples


Cavity can be encountered in practically most lung diseases.

Common diseases and their characteristics

Comprehension of the above principles.

  1. Rationale for multiple bilateral cavities.
  2. Why does reactivation Tb occurs in superior segments?
  3. Why does aspiration lung abscess occur in the superior segment of lower lobes?
  4. What is the criteria for thick and thin wall ?
  5. What is the pathogenesis of stalactites and stalagmites?
  6. What is crescentic sign?
  7. How do you differentiate between aspergilloma and sub acute necrotizing aspergillosis?
  8. Does the location of cavity in a density have diagnostic significance?
  9. What is open negative Tb?
  10. In metastatic disease, when do you get thin walled cavities and when do you get thick walled cavities?