Swyer-James syndrome

Swyer-James syndrome (SJS), also known as Swyer-James-MacLeod syndrome and Bret syndrome, is a rare lung condition that manifests as unilateral hemithorax lucency as a result of postinfectious obliterative bronchiolitis


The condition typically follows a viral respiratory infection such as adenoviruses or Mycoplasma pneumoniae infection in infancy or childhood 2-6

Radiographic features

Plain radiograph

It is generally characterised on radiographs by a unilateral small lung with hyperlucency and air trapping 2.


CT shows the affected lung as being hyperlucent with diminished vascularity. The size of the majority of the affected lobes is smaller, although occasionally they can be normal 3. There is usually no anteroposterior gradient attenuation 4. Bronchiectasis may be present although this is not a universal finding 5.

Nuclear medicine

Quantitative ventilation/perfusion lung scan shows a photopaenic area in the affected aspect.

History and etymology

The condition was first described in Canada in the 1950s by:

  • Paul Robert Swyer: English paediatrician in Canada
  • William Mathieson MacLeod: English pulmonologist (1917-1977)
  • George C W James: Canadian radiologist

It has also been referred to as MacLeod syndrome, but this is not advised given the presence of a rare genetic malformation bearing a similar name: McLeod syndrome. It was also described by J Bret in France, hence reference to the same condition as Janus syndrome and Bret syndrome

Differential diagnosis

Possible imaging differential considerations include

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Article Information

rID: 13793
System: Chest
Section: Syndromes
Synonyms or Alternate Spellings:
  • MacLeod syndrome
  • Swyer James MacLeod syndrome
  • Janus syndrome
  • Bret syndrome
  • Bret's syndrome
  • Swyer-James-MacLeod syndrome
  • MacLeod's sydrome
  • Swyer James syndrome
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