Localized bronchomalacia presenting as worsening asthma.

A patient with longstanding mild asthma presented with a several month history of almost continuous wheezing. Pulmonary function tests suggested large airway variable intrathoracic obstruction. At bronchoscopy, she was found to have severe bronchomalacia limited to the left main bronchus. There was almost complete obstruction of that airway during forced expiration.