Congenital mesenterico-portal (Rex) shunt.

Congenital anomalies of the portal and umbilical-venous system are rare, with few reported cases. We describe a case where the native umbilical vein had acquired mesenteric venous outflow to bypass an in-utero portal-vein (PV) obstruction and restore normal venous return to the liver. This is analogous to the recently described Rex shunt procedure used in some cases of extrahepatic portal hypertension due to PV occlusion.