In which one of the following conditions does cystic medial necrosis occur?a. Marfan syndrome
The aortic wall is composed of three layers—the adventitia, the media, and the intima. Aortic dissection occurs when these layers are interrupted, and blood flows typically between the media and adventitia. The media layer is composed of smooth muscle, collagen, and elastin, and thus conditions that affect the strength of this layer will predispose to aneurysm formation and dissection. Cystic medial necrosis occurs in Marfan syndrome, but it is also known to occur in other fibrillinopathies and is said to confer a more aggressive disease course. It occurs in 75% of patients with bicuspid aortic valve undergoing aortic valve surgery. Atherosclerosis results in reduced flow in the vasa vasorum and contributes to a cystic medial necrosis/degeneration-like condition.