Extrapleural Sign

Expanding lesions of structures in the chest wall give rise to this sign. This sign helps to recognize the site of the lesion. The characteristic features of the density are: 

  1.  Peripheral location 
  2. Cat under the rug appearance 
  3. Concave edges 
  4. Sharp inner edge and indistinct outer edge 
  5. Equal length and width in early stages 
Chest wall lesions 
  • Rib
  • Mets 
  • Callous 
  • Hematoma 
  • Plasmacytoma
Parietal pleura
  • Mesothelioma 
  • Metastatic masses
Intercostal nerve
  • Neurofibroma 
Intercostal muscle
  • Rhabdomyosarcoma 
Internal mammary ode 
Mediastinal lesions 
  • Masses 
  • Cystic hygroma 
Diaphragm lesions 
  • Lipoma