A rupture of the ascending aorta which occurred in a woman on the 13th postoperative day following a right upper lobectomy with mediastinal lymph node dissection for lung cancer is reported herein. Fortunately, the patient was rescued from a cardiac tamponade and hemothorax by emergency operation. The operative findings suggested a traumatic rupture of the aorta, however, lymph node dissection of the mediastinum could not be excluded as a possible cause. Therefore, careful mediastinal lymph node dissection should be carefully performed in operations for lung cancer.
