[Medial necrosis of the pulmonary artery in ruptured aneurysm].

Fifty years ago the first author of this paper described the entity known as idiopathic medial necrosis of the aorta. The present report describes two cases of ruptured aneurysm of the main pulmonary artery. The histologic alterations of the arterial wall were the same as in the much more common aneurysms of the aorta, viz.