Round atelectasis
Round atelectasis, also known as rounded atelectasis, 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.
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Pathology
Two theories have been put forward. The second theory is more favored while the multi-factorial etiology 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
- organization 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
Etiology
- exposure to mineral dust: asbestosis, pneumoconiosis 13
- exudative pleuritis: tuberculosis, hemothorax 13
- less commonly seen in histoplasmosis, legionella, end-stage renal disease 13
- sarcoidosis 13
Associations
It can be associated with:
- asbestos lung exposure 3: most commonly
- therapeutic pneumothorax in the treatment of tuberculosis 1
- congestive heart failure 2
- pulmonary infarction 2
- parapneumonic effusion
Location
There may be a predilection towards the lower lobes 4.
Radiographic features
CT
- round or oval in shape
- almost always seen adjacent to a pleural surface
- there is associated adjacent pleural abnormality, e.g. pleural thickening or pleural effusion
- comet tail sign 2: produced by the pulling of bronchovascular bundles giving the shape of a comet tail
- crow feet sign
- as it represents collapsed lung, it commonly demonstrates a typical parenchymal enhancement
- posterior lower lobes are most commonly involved and, sometimes, bilateral or symmetrical 14
Rounded atelectasis can occasionally increase in size on serial scans 6,7.
Nuclear medicine
FDG-PET
- not metabolically active
- may play a role in differentiating from malignancy when there are few or atypical features on chest radiographs and CT 9
History and etymology
It was first described by Loeschke in 1928 6.
See also
Related Radiopaedia articles
Airspace opacification
- airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
Chest
- imaging techniques
-
chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
-
approach
- HRCT
-
chest x-ray
- airways
- bronchitis
- small airways disease
-
bronchiectasis
- broncho-arterial ratio
- related conditions
- differentials by distribution
- narrowing
-
tracheal stenosis
- diffuse tracheal narrowing (differential)
-
bronchial stenosis
- diffuse airway narrowing (differential)
-
tracheal stenosis
- diverticula
- pulmonary edema
-
interstitial lung disease (ILD)
- drug-induced interstitial lung disease
-
hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
- subacute hypersensitivity pneumonitis
- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
-
pneumoconioses
- fibrotic
- non-fibrotic
-
lung cancer
-
non-small-cell lung cancer
-
adenocarcinoma
- pre-invasive tumors
- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of the lung
- squamous cell carcinoma
- salivary gland-type tumors
-
adenocarcinoma
- pulmonary neuroendocrine tumors
- preinvasive lesions
-
lung cancer invasion patterns
- tumor spread through air spaces (STAS)
- presence of non-lepidic patterns such as acinar, papillary, solid, or micropapillary
- myofibroblastic stroma associated with invasive tumor cells
- pleural invasion
- vascular invasion
- tumors by location
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
-
non-small-cell lung cancer