An extremely rare variety of anomalous coronary artery: right coronary artery originating from the distal left circumflex artery.

A single coronary artery (SCA) is a rare congenital anomaly of the coronary circulation, which is often associated with myocardial ischemia and other congenital cardiac anomalies. A 77-year-old woman visited our hospital complaining of typical chest pain. Coronary angiography revealed an isolated SCA. The right coronary artery did not originate from the aorta, but instead emerged from the distal left circumflex artery, with significant stenosis at the proximal portion of the left anterior descending artery. A stent was successfully implanted at the culprit lesion. There was no perfusion defect detected by a cardiac SPECT study.