[An autopsy case developing both marked stenosis of the coronary artery and dilated phase of hypertrophic cardiomyopathy].

An autopsy case involving the dilated phase of hypertrophic cardiomyopathy (HCM) is reported. This case was also complicated with a lesion similar to fibromuscular dysplasia of the coronary artery. A 37 year-old male died of cardiac insufficiency and an autopsy was performed. Macroscopically, both atriums and ventricles were dilated and the walls of both ventricles were markedly thickened. Also, the coronary artery was almost completely obstructed. Histological examination revealed bizarre myocardial hyperplasia with disorganization and marked fibrosis of the myocardium. The coronary artery showed intimal fibrous thickening with increase in elastic fibers and smooth muscle cells. There were similar lesions in other arteries examined; the renal arteries, external iliac arteries, pulmonary arteries and aorta. We think that this lesion of the coronary artery plays an important part in the progression from hypertrophic cardiomyopathy to dilated cardiomyopathy.