|MIP – coronalis reconstructio|
Discussion of Round atelectasis
- Pathogenesis of round atelectasis is not certain, but it is thought to be due to an inflammatory reaction and fibrosis in the superficial layer of the pleura.
- As the fibrous tissue matures, it contracts, causing pleura to fold into the lung, which in turn causes atelectasis.
- Round atelectasis is almost always asymptomatic and is detected on chest radiographs obtained for other reasons.
- A history of asbestos exposure is frequently (in 70% of cases) present. Asbestos-related round atelectasis is also known as asbestos pseudotumor or Blesovsky syndrome.
- Conditions such as congestive heart failure, pulmonary infarction, Dressler syndrome, parapneumonic effusion, tuberculous effusion, and nonspecific pleurisy can precede round atelectsis formation.
- Lung cancer is the main differential diagnosis.
- After diagnosis, a follow-up CT should be obtained to exclude lung cancer.
- The typical chest radiographic appearance is of a rounded peripheral „mass” with or without lung distortion.
- Pleural thickening is usually seen.
- The CT features are:
- A round or oval mass that abuts the pleura
- Has sharp lung borders
- Has a fuzzy border which projects to the hila (Origin of Comet tail sign)
- a „comet tail” of bronchovascular structures going into the mass (Comet tail sign).
- Thickening of the adjacent pleura.
- Volume loss is often, but not invariably, apparent.