Cystic medial necrosis responsible for aoic dilatation and rupture is seen in

In Marfan syndrome, a connective tissue disorder of autosomal dominant inheritance, the basic biochemical abnormality is a mutation affecting fibrillin. Most serious, however, is the involvement of the cardiovascular system. Fragmentation of the elastic fibers in the tunica media of the aoa predisposes affected patients to aneurysmal dilation and aoic dissection . These changes, called cystic medionecrosis, are not specific for Marfan syndrome. Similar lesions occur in hypeension and with aging. Loss of medial suppo causes dilation of the aoic valve ring, giving rise to aoic incompetence. Robbins Basic pathology,9th edition,pg no.221