Absent right superior vena cava and persistent left superior vena cava opening into the left auricle with transposition of the azygos system of veins.

Abstract

Left superior vena cava (LSVC) opening into the left atrium without an atrial septal defect or right superior vena cava is extremely rare. During routine dissection for undergraduate medical teaching we came across a similar variation coexisting with variation of the azygos system of veins. Azygos vein (AV) was noted on the left and drained into LSVC before the latter opened into the left auricle. Accessory and hemiazygos veins were present on the right, but crossed over to the left across the vertebral column to drain into AV at the level of T5 and T8, respectively. LSVC may remain silent clinically and usually discovered incidentally. Its presence may complicate central venous access, implantation of pacemaker etc. Variation in azygos system of veins can become problematic during surgical procedures by causing unexpected haemorrhage. The present case highlights the importance of recognising this infrequent systemic venous anomaly by clinicians.