[Giant cell arteritis and takayasu's disease: histopathological criteria (author's transl)].

Both of these arterial diseases may involve the aorta and the major arterial trunks. Two cases of subclavian involvement are used to contrast them from a histopathological standpoint. In giant cell arteritis, the lesions affect above all the internal elastic layer and the inner part of the media, destroyed by an inflammatory infiltrate with giant cells. In Takayasu's disease, the lesions involve the adventitia, the site of fibrosis and of inflammatory islets with the vasa vasorum at the centres. Involvement of the media is predominantly in its outer part, the internal elastic layer being intact. A histopathological definition of these arterial diseases may be envisaged on the basis of these facts.