Abnormal direct entry of the umbilical vein into the portal vein: report of a case.

Abnormalities of the intra-abdominal umbilical venous connections are rare congenital vascular anomalies. We report a case of an aneurismal dilatation of an umbilical vein directly connected to the portal vein, vital for the delivery of placental blood in the fetus. A term female newborn presented with a dilated umbilical vein detected by prenatal ultrasound. CT angiography revealed an aneurismal dilatation of a vascular structure, from the umbilical ring to the main portal vein. Follow-up CT angiography showed thrombus progression up to the level of SMV inlet. A laparotomy revealed that the normal course of the umbilical vein was absent. The aneurysm was resected and no thrombus was noted in the aneurysm. Post-operative ultrasound revealed an isolated thrombus at the right main portal vein that resolved spontaneously on the follow-up ultrasound. At the 6-month post-operative follow-up, the baby was well and without complications. Although not evaluated for the presence of a ductus venosus, this anomalous umbilical-portal venous connection might have been associated with an absent ductus venosus.