Agenesis of the venous duct with abnormal return of the umbilical vein into the superior vena cava: A case report

Introduction Agenesis of the venous duct is rare, with an incidence rate of .04%-.6%. Abnormal drainage of the umbilical vein (UV) to superior vena cava (SVC) is seen in .5% of agenesis of the venous duct cases. We present a case of agenesis of the venous duct with drainage of the UV into the SVC accompanied by tetralogy of Fallot. Case presentation The fetus was diagnosed with agenesis of the venous duct and tetralogy of Fallot at 29 gestational weeks. The UV directly returned to the SVC. Cardiomegaly and pericardial effusion were observed but did not deteriorate. The female infant was born at 40 gestational weeks. Contrast-enhanced computed tomography showed that the UV was occluded at its proximal aspect. No abnormality of the portal system was noted. The infant underwent intracardiac repair and was doing well at 16 months of age. Discussion/Conclusion Although the extrahepatic drainage type of agenesis of the venous duct is occasionally associated with heart failure and hydrops, severe hydrops was absent in this case. It was speculated that vascular resistance in the long pathway to the SVC restricted direct inflow from the UV. Portosystemic shunts and agenesis of the portal system are reported complications of agenesis of the venous duct. Prenatal agenesis of the venous duct diagnosis may be crucial for early postnatal diagnosis of these conditions.