A huge coronary aneurysm resulting from a coronary artery-to-left ventricle fistula.

A huge coronary aneurysm resulting from a coronary artery-to-left ventricle fistula is a rare condition. A 57-year-old male had severe recurrent angina attacks. The cause of angina pectoris was a right coronary artery-to-left ventricle fistula with a huge coronary aneurysm. The histological examination of surgically excised specimens revealed that two vertical smooth muscle layers of media of the aneurysm might be associated with dysplasia. Mucoid degeneration was also shown in the intima and around the vasa-vasorum. Abnormal hemodynamics related to the fistula might have induced these vessel wall changes resulting in the huge coronary aneurysm.