Idiopathic arterial calcification in a 3-month-old child, associated with myocardial infarction.

Idiopathic arterial calcification, which is characterized by intimal fibroblastic proliferation in arteries with mural calcification, may be a cause of sudden death in children. We presented here a three-month-old male infant terminating in sudden death, whose postmortem examination revealed characteristic occlusive disorder of the coronary arteries, associated with secondary myocardial infarction. Histologic study of the coronary arteries demonstrated fibrous intimal proliferation and numberous calcified foci in the internal elastic lamina or in the intima, causing luminal occlusion of the arteries. Similar morphologic changes were found in medium-sized elastic or muscular arteries of other organs. These light microscopic features are consistent with that of so-called idiopathic arterial calcification. Electron microscopic examination of the coronary arteries revealed foamy degeneration of the internal elastic lamina, with focal aggregates of granular high density material. It is suggested that these light and electron microscopic changes of the internal elastic lamina may disclose the fundamental process resulting in mineralization of the lamina, with secondary fibroblastic hyperplasia in the intima.