Histpathological findings of aortic aneurysm from patient with GPA. (A) Histologic section showing considerable arteriosclerosis in the intima and media, with cholesterol clefts. There is intimal thickening with reduplication of the internal elastic lamina. The media is thickened, and the medial smooth muscle cells are replaced by pink hyaline material (hematoxylin and eosin, original magnification ×100). (B) Arteritis with giant-cell formation and lymphocyte and plasma cell infiltration around the vasa vasorum in the media is evident. The aortic media shows patchy infiltration by lymphocytes (plasma cells), with early disruption of the media (hematoxylin and eosin, original magnification ×270).