No abstract available. Article truncated after 150 words. A 19 year old man with acute lymphocytic leukemia was admitted to the ICU with septic shock. Due to areas of cellulitis on the right side of the chest and neck and femoral venous thrombi, a left subclavian central access was attempted. The chest x-ray obtained after line placement is shown below (Figure 1). Blood gas done from the line was consistent with venous blood and venous tranduction was seen. A CT of the chest (Figure 2) confirmed the diagnosis of persistent left superior vena cava (PLSVC). A persistent left superior vena cava is the most common congenital thoracic venous anomaly, seen in 0.3-0.5% of the population (1). Incidence is increased in patients with congenital heart disease to 5%. In most patients a right sided SVC is also present; hence the term SVC duplication has also been used. Embryologically a PLSVC is formed when the left anterior cardinal vein is ...