Abnormal balloon- or sac-like dilatation in the wall of coronary vessels. Most coronary aneurysms are due to coronary atherosclerosis, and the rest are due to inflammatory diseases, such as kawasaki disease. The disease is coronary aneurysm (Monarch Disease Ontology identifier MONDO_0006714). Also known as: aneurysm of coronary vessels, aneurysmal lesion of coronary artery, arteriovenous aneurysm of coronary vessels.