Twin circumflex arteries: a rare coronary artery anomaly.

Dual origin of the circumflex artery is an extremely rare anomaly. We report a rare case of a left circumflex artery arising from the left mainstem and an anomalous circumflex artery from a separate ostium in the right coronary sinus. Both these arteries supplied the circumflex territory. The potential pathological significance of the anomaly and pitfalls of the misdiagnosis are also discussed.