A rare, asymptomatic case of an extrahepatic portocaval shunt between the posterior aspect of the portal vein and the inferior vena cava

PURPOSE: We present the case of a rare extrahepatic portocaval shunt that resulted in communication of the portal vein and the inferior vena cava (IVC) at the level between two right renal veins that was incidentally diagnosed with contrast-enhanced computed tomography (CECT) in an asymptomatic patient. METHODS: A woman in her sixties with abdominal pain and diarrhea of unclear origin underwent exploratory abdominal CECT. RESULTS: The CECT incidentally revealed an extrahepatic portocaval shunt, whereby a vessel arising from the portal vein superior to the confluence of the superior mesenteric and splenic veins drained into the posterior aspect of the IVC between two right renal veins. CONCLUSION: The identified vessel was likely a remnant communication between the supra-subcardinal anastomosis and the primitive portal vein. This type of portocaval shunt is rare; although there are no reports of its asymptomatic presence in an adult, recognition thereof may help to identify the cause of symptoms related to hepatic encephalopathy or liver dysfunction. Such a shunt may also provide a minimally invasive approach to the portal vein in procedures that typically rely on access via the transhepatic route.