A rare cause of dyspnea and fibrocystic pulmonary disease.

Tracheobronchomegaly (TBM) is a disorder of the major airways characterized by an enlargement of the trachea and main stem bronchi. It is thought to result from a congenital connective tissue defect that results in the trachea and main bronchi becoming flaccid. Although TBM is considered rare, it may be more common than is generally recognized, and may be a seldom-diagnosed cause of chronic lung disease.