The author has displayed a cases of 23-year-old male employee who had no particular past history but was affected by the hypertrophic type of idiopathic cardiomyopathy, which was at first revealed by the autopsy at the Tokyo-to Medical Examiner Office. Macroscopically, extreme hypertrophy of the anterior portion of ventricular septum was noticed. Hypertrophied myocardium showed bizzare arrangement of muscle fibers of different sizes and scar formation associated with circumscribed elastosis in the walls of small arteries and artioles.
