Abnormal entrance of the umbilical vein into the liver and fetal thrombotic vasculopathy in a fetus: a rare combined case.

The left umbilical vein is lodged on the fissure of the round ligament of the liver, from umbilicus to portal vein, just on the inferior margin of the falciform ligament. We report an anomalous course of the umbilical vein in a 39-week-old deceased male fetus, also exhibiting fetal thrombotic vasculopathy (FTV). In the present case, the umbilical vein entered the liver through a tunnel on its anterior part of the diaphragmatic surface, close to the lower free edge of the liver and next to the falciform ligament. The entrance of the tunnel was covered by Glisson's capsule. The round ligament's fissure was absent. The quadrate lobe was not well demarcated and the visceral surface of the liver had an abnormal appearance. The coexistence of FTV was confirmed histologically. The possibility of a tunnel present for the umbilical vein, instead of a fissure, is of great significance for surgical approaches or for radiological evaluations, even though it is not likely to cause intrauterine fetal death. However, the anomalous course of umbilical vein might be a predisposing factor for FTV, which often leads to intrauterine fetal death.