Round atelectasis

Dr Henry Knipe and Dr Yuranga Weerakkody et al.

Round atelectasis, also known as folded lung or Blesovsky syndrome, is an unusual type of lung atelectasis where there is infolding of a redundant pleura. The way the lung collapses can at times give a false mass-like appearance.

Two theories have been put forward. The second theory is more favoured while the multi-factorial aetiology suggests both mechanisms probably operate in different patients:

  • Hanke and Kretzschmar
    • underlying pleural effusion causes local atelectasis in the adjacent lung
    • a cleft or infolding of the visceral pleura will then form if the rate of pleural fluid formation exceeds alveolar air absorption
    • this then causes the lung to tilt on the cleft
    • the lung then curls on itself in a concentric fashion
    • fibrous adhesions suspending the atelectatic segment (and usually tilt the lung cranially) develop
    • as the effusion resorbs, the aerated lung fills in the space between the area of round atelectasis
    • organisation of the fibrinous exudate and fibrous contraction lead to additional lung parenchymal distortion
  • Schneider et al (expanded on by Dernevik and colleagues)
    • a local pleuritis caused by irritants such as asbestos
    • in the event of a benign asbestos-related pleural effusion, the pleura contracts and thickens with shrinkage of the underlying lung, and atelectasis develops in a round configuration
  • exposure to mineral dusts : asbestos, pneumoconiosis13 
  • exudative pleuritis: tuberculosis, haemothorax 13 
  • less commonly seen in histoplasmosis, legionella, end stage renal disease 13
  • sarcoidosis 13

It can be associated with:

There may be a predilection towards the lower lobes 4.

Rounded atelectasis can occasionally increase in size on serial scans 6,7.


  • not metabolically active
  • may play a role in differentiating from malignancy when there are few or atypical features on chest radiographs and CT 9

It was first described by Loeschke in 1928 6.

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Article information

rID: 10354
System: Chest
Section: Pathology
Synonyms or Alternate Spellings:
  • Folded lung
  • Blesovsky syndrome
  • Rounded atelectasis
  • Rounded lung collapse
  • Round atelectatic change
  • Rounded atelectatic change

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