Findings: PA radiographs in inspiration/expiration show hyperlucency of the left lung. The heart is displaced towards the right and there is shifting of the mediastinum towards the right on expiration, confirming air trapping of the left lung. In addition, a tubular structure is visible in the left lower lung (arrow).
Axial and coronal CT show hyperlucency of the left lower lung, limited by normal upper lung (white arrows). There is a non-enhancing tubular structure in the centre of the left lower lung (red arrows). The displacement of the heart towards the right is due to the expanded left lung plus a marked pectus excavatum.
Final diagnosis: Congenital bronchial atresia, left lower lobe.
Teaching point: Congenital lung lesions are not rare in adults. Focal hyperlucent lungs with air trapping and mucous impaction are findings highly suggestive of bronchial atresia.