Simultaneous occurrence of a single coronary artery and persistent left superior vena cava.

We present a case of simultaneous occurrence of 2 rare congenital anomalies. A 57-year-old woman undergoing evaluation of dyspnea was found to have a single coronary artery and persistent left superior vena cava. The incidence of single coronary artery is 0.024% to 0.066% in the general population. Persistent left superior vena cava occurs in 0.3% of those without other congenital anomalies and in up to 5% when other anomalies are present. The likelihood of both anomalies occurring as a random event in 1 patient is approximately 1 in 10 million. Patient characteristics and data are presented, with a discussion on the epidemiology, incidence, diagnosis and pathologic implications of each anomaly.