Myxomatous degeneration and cystic medial necrosis associated with acromegaly.

Although valvular lesions are rare in acromegaly, two patients with click-murmur syndrome and one patient with aortic insufficiency secondary to myxomatous degeneration and cystic medial necrosis of the aorta have been reported. Growth hormone excess has been postulated to potentiate these connective tissue defects. Excess mucopolysaccharide deposition is stimulated by growth hormone and is characteristic of both cystic medial necrosis and myxomatous degeneration. Both lesions are found in experimental lathyrism, which is potentiated by growth hormone. We observed a patient with mitral insufficiency, acromegaly documented by growth hormone levels, myxomatous degeneration of all four cardiac valves, and cystic medial necrosis of the aorta and pulmonary artery. This case presents further evidence that excess growth hormone may potentiate the connective tissue cardiovascular lesions in acromegaly.