[Erdheim-Gsell medial necrosis and mucoid degeneration of the media as a cause of aorto-arterial aneurysm. Pathologico-anatomical analysis of 150 excised vessels].

150 cases of true and dissecting aneurysms due to degenerative, non-arteriosclerotic lesions of the media were analyzed. Histologically, two types of alterations may be distinguished. The classical medionecrosis of Erdheim and Gsell is characterized by focal destructions of elastic fibers, while so-called mucoid degeneration of the media shows mucoid deposits between the rarified and atrophic elastic fibers but no focal destruction of the latter. These two lesions are clearly distinguishable in the majority of cases. Average age and distribution among age groups are identical in both types. In both groups the male patients predominate but with a different ratio. True and dissecting types of aneurysm are equally distributed in medionecrosis of Erdheim and Gsell (including the cases with Marfan's syndrome), but dissecting aneurysms predominate by a ratio of 8:1 in mucoid degeneration. Several arguments strengthen the opinion that the two types of lesion represent different disease entities. The etiology of the disorder is still unknown; our findings do not show a relation to arteriosclerosis or to a simple aging process of the vessel wall.