Accessory lung arising from the upper esophagus. A rare congenital anomaly in the adult.

A lung infiltrate found incidentally in an adult was shown radiologically to be the result of a fistula arising from the upper esophagus. At the pulmonary site, the fistula demonstrated several branches with the typical configuration of a rudimentary bronchial three. The findings are consistent with an unusual type of congenital bronchopulmonary malformation. Ordinarily, accessory lungs are located at the lung base communicating in selected cases with the lower esophagus or the stomach. The embryological explanation lies in an incomplete separation of the tracheobronchial tree from the esophagus.