Bronchial Atresia of the Right Ninth Bronchus with Segmental Hyperinflation in an Asymptomatic Adult-A Case.

Bronchial atresia (BA) is a rare congenital anomaly that develops as a consequence of an intrauterine bronchial artery insult. Distal to the atresia, a mucocele can form with consecutive hyperinflation of the peripheral lung parenchyma. We describe an asymptomatic patient with a well-demarcated segmental emphysematous area within the right lower lobe revealed by computed tomography (CT). Here, the right lateral basal segmental bronchus (B9) is proximally interrupted while the distal, mucus-filled bronchus forms a bronchocele. The down-stream segmental parenchyma is hyperinflated. 3D reconstruction of the tracheobronchial tree reveals a normal architecture of the tracheobronchial tree except for the characteristic discontinuation of the right ninth bronchus. Asymptomatic patients with BA do not require treatment, however, follow-up CT is recommended to assess stability of the segmental hyperinflation.