Persistent left superior vena cava (LSVC) may be observed in 0.3% of unselected cases and is the most common thoracic venous anomaly. It forms from a confluence of the left subclavian and left jugular veins and courses inferiorly in a position analogous to the normal right superior vena cava.
Inferiorly, the left superior vena cava lies anterior to the left hilum and drains into a dilated coronary sinus. Its anatomical course reflects its origin as a persistent remnant of the left anterior cardinal vein, a vessel that is present in early embryological development but normally disappears.
A right superior vena cava may or may not be present, while the left brachiocephalic vein is usually absent, as in this case. If it is not associated with other congenital cardiac anomalies, left superior vena cava is usually asymptomatic. Its diagnosis can be confirmed by many noninvasive and invasive tests like echocardiography, angiography and computed tomography. Magnetic resonance (MR) imaging has been reported as a useful tool for delineating both the thoracic venous and associated intracardiac anomalies; howerever, in our experience, CT with currently available 3D volume rendering reconstructions allows correct diagnosis of this vascular anomaly, avoiding more invasive tests.