Bilateral absence of superior vena cava.

The absence of a right superior vena cava (SVC) in situs solitus is very rare, and even then it is usually associated with left SVC. There have been few case reports in the literature of isolated bilateral absence of SVC. Bilateral absent SVC can have clinical implication, including pacemaker placements, central venous line placement, monitoring, and occasionally associated anomalies. We describe a case detected on fetal echocardiogram with bilateral absent SVC and structurally normal heart.