Intrahepatic inferior vena cava interruption with transhepatic venous continuation initially misdiagnosed as a congenital portosystemic shunt

We report a case of intrahepatic inferior vena cava interruption with azygos and transhepatic venous continuation discovered incidentally on CT angiography for acute aortic syndrome. The lesion was initially misdiagnosed as a congenital portosystemic shunt on multiphase CT of the liver but subsequent fluoroscopic venogram revealed no evidence of portosystemic shunting. While intrahepatic IVC interruption with azygos continuation is an uncommon but well-known anatomical variant, transhepatic venous continuation is extremely rare and only a few cases have been published. Excluding portosystemic shunting is important for determining management as persistent congenital portosystemic shunts can be associated with significant morbidity.