Compression of the left main bronchus between a descending thoracic aortic aneurysm and an enlarged right pulmonary artery.

A man with chronic obstructive lung disease presented to the hospital with respiratory failure and a chest x-ray indicated complete radiopacity of the left hemithorax. An endobronchial malignancy was suspected, but unexpectedly left-main bronchial occlusion was found secondary to compression between a descending thoracic aortic aneurysm and an enlarged right pulmonary artery.