Antenatal Bilateral Renal Vein and Vena Cava Thrombosis in Dichorionic Twin Pregnancy

Background: Antenatal renal vein thrombosis have been a rarely described diagnostic finding, with variable consequences on kidney function. Case report: We present an unusual case of a dichorionic twin pregnancy in 34 weeks of gestation with one affected fetus, showing already intrauterine a bilatrally hyperechoic kidneys with a left kidney increased in size and cardiotocographic signs of fetal distress, while dichorionic male co-twin was healthy. At birth, there was no heartbeat of the affected fetus despite resuscitation. Clinical examination of the stillborn showed that both kidneys were bulky. Autopsy revealed enlarged hemorrhagic kidneys, distension of the Gerota fascia and thrombosis of the renal and adrenal veins, extending to the inferior vena cava, with no sign of fetal hydrops except for a moderate pleural effusion. Histologically, there was hemorrhagic infarction by massive bleeding with thrombosis of both renal veins and supra-renal vena cava. The postnatal thrombophilia investigations revealed a heterozygous mutation in the MTHFR gene with no associated hyperhomocysteinemia. Conclusion: There are still many unresolved issues regarding antenatal vein thrombosis. Diagnostic possibilities and prognostic probabilities still show large discrepancies.