Round Atelectasis

History: 60 year old male undergoing CT of the thorax for follow up of chest x-ray abnormality. 

Single axial CT of the thorax shows a left peripheral pleural based oval shaped opacity with crowding together of bronchi that extend from the mass toward the hilum.

This is a classic appearance of round atelectasis. Look again at the image above. Notice the calcified pleural plaque along the area of atelectasis. Round atelectasis is most frequently seen in asbestos related pleural plaques. Other terms for round atelectasis include folded lung, Blesovsky syndrome, atelectatic pseudotumor, asbestos pseudotumor, pleuroma, shrinking pleuritis with atelectasis.