Bilateral agenesis of the superior vena cava associated with congenital hydrothorax.

Agenesis of the superior vena cava is a rare anomaly that is generally asymptomatic in the neonate. We report a male neonate with bilateral (total) agenesis of the superior vena cava with obstructed thoracic duct and subsequent congenital hydrothorax, anomalies that were detected by prenatal ultrasound at 25 weeks' gestation. The cardiac anomaly was confirmed by postnatal magnetic resonance angiography. The chylothorax disappeared with conservative therapy.