Tracheal bronchus.

Congenital tracheal bronchus is an uncommon condition that may occur together with other, sometimes clinically significant anomalies of the tracheobronchial tree. Two such patients are reported. Both presented with respiratory distress, and one was initially diagnosed as having a pulmonary cyst. Radiographic demonstration of an upper-lobe cyst, particularly on the right, should suggest a tracheal bronchus.