Incomplete border sign

The incomplete border sign is useful to depict an extrapulmonary mass on chest radiograph.

An extrapulmonary mass will often have a inner well defined border and an ill-defined outer margin 1-3. This can be attributed to the inner margin being tangential to the x-ray beam and has good inherent contrast with the adjacent lung. On the other hand, the outer margin is enface or partially enface with the X-ray beam and merges with the pleural or chest wall thus the border is obscured. 

Differential diagnosis

Differential diagnosis for extrapulmonary mass can be further divided into pleural or extrapleural.

Common pleural masses include:

Extrapleural causes can arises from component of chest wall, bone/cartilage, nerve, vascular, fat, muscle and skin. If there is sign of rib/bone involvement on chest radiograph the lesion is most likely to be extrapleural. In adults, skeletal metastases are the most common malignant chest wall neoplasm while chondrosarcoma is the most common primary malignant tumor.


Chest x-ray
Share article

Article Information

rID: 22423
System: Chest
Sections: Gamuts, Signs
Tags: refs, cases
Synonyms or Alternate Spellings:
  • Incomplete border sign on a chest x ray
  • Incomplete border sign on a chest radiograph

Support Radiopaedia and see fewer ads

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.