Hemitruncus is a rare congenital anomaly in which one pulmonary artery branch, usually the right, arises from the ascending aorta just above the aortic sinuses, whereas the main pulmonary artery and the other pulmonary branch arise in their normal position. The authors present a case in which the patient was diagnosed as having hemitruncus as an adult, and to the best of their knowledge only 7 similar cases have been reported in the medical literature.

The authors report a case of a fifty-one-year-old man undergoing rehabilitation therapy following a stroke who suddenly developed right-sided pleuritic chest pain with dyspnea. Transesophageal echocardiography was used to demonstrate a nonocclusive right pulmonary artery embolus, when other investigative modalities failed to establish the diagnosis.