Histopathologic findings of abdominal aortic aneurysm and ascending aortic dissection.

(a–c) Abdominal aortic aneurysm. (a) Thinning of the aortic wall media (between two arrowheads) in contact with the atheromas (asterisk) and fibrous cap. (a. Masson trichrome staining, × 40) (b) The thickness of the thinned aortic wall was 150 μm. Atherosclerosis (arrowhead) was in contact with the aneurysmal wall (H&E, × 100) (c) Diminishing internal elastic lamellae (arrow) (magnified view of the square inside the (b) figure, elastic staining, × 400). (d–f) Ascending aortic dissection. (d) Aortic wall thickness was maintained, but medial tearing was present (Masson trichrome staining, × 12.5). (e) In the dissected aortic wall, neither atheromas nor thinning of the aortic walls was observed (H&E, × 40) (f) Medial tearing with loss of elastic lamella (arrow). (magnified view of the square inside the (e) figure, elastic staining magnification × 200).

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