Ruptured saccular pulmonary artery aneurysm associated with persistent ductus arteriosus.

We report a case of rupture of a saccular pulmonary artery aneurysm with fatal hemopericardium in a 29-year-old man who also had persistent ductus arteriosus with severe pulmonary hypertension. Histologic examination of the pulmonary artery showed cystic medionecrosis similar to that observed in patients with ruptured dissecting pulmonary artery aneurysms. The two types of ruptured aneurysms probably only represent different morphological expressions in the same underlying process in which the main contributory factor is pulmonary hypertension.