Mounier-Kuhn disease

Case contributed by Sarah AlJahdali


Immunocompromised patient, for screening

Patient Data

Age: 50 years
Gender: Male

There is a large lucency projecting over the superior mediastinum on the right side on the frontal radiograph, causing mild displacement/widening of the right para-tracheal line. This correlates with likely dilation of the trachea, better appreciated on the lateral radiograph. The rest of the examination is otherwise unremarkable.


The tracheal is significantly dilated (measuring >3 cm) and associated with an outpouching/diverticulum projecting posteriorly. There is also mild dilation of the central bronchi bilaterally. These findings are in keeping with tracheobronchomegaly.

Case Discussion

Tracheomalacia is defined as tracheomegaly (increased tracheal size > 3 cm) and increased compliance (tendency of the airway to collapse on expiration), best assessed on a biphasic CT with images of the trachea obtained during inspiration and expiration.

Tracheomalacia could be secondary to congenital causes, including Mounier-Kuhn syndrome, as in this case, or other acquired causes.

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