[Aneurysm of a diverticulum of the ductus arteriosus in an adult: a case report].

An aenurysm of a diverticulum of the ductus arteriosus in a 33-year-old man was presented. The chest radiography revealed a mass obscurring the aortic window above the hilus of the left lung. His blood pressure was 130/70 mmHg, and there was no difference in pressures between the upper and lower or between the right and left extremities. A CT scan of the chest showed 30 X 34 mm angioma adjacent to the descending aorta and pulmonary artery. Aortography and contrast radiography of the right ventricle revealed a cystic pedunculated aneurysm at the superior portion of the descending aorta. The base of the left pulmonary artery was slightly displaced. There was no communication between the aorta and pulmonary artery, nor was any significant difference in pressure between the ascending and descending aorta. This case was diagnosed as an aneurysm of the diverticulum of the ductus arteriosus, and then it was resected. The abnormality was confirmed by the localization of the aneurysm and histopathologic findings, but the presence of the ligamentum arteriosum was not confirmed. This is the 23rd case of the aneurysm of the diverticulum of the ductus arteriosus in adults, and the first case in Japan in which the diagnosis was made in a living patient, followed by successful surgery.