Definition:

Extrahepatic portal vein obstruction (EHPVO) is a vascular disorder of liver characterized by obstruction and cavernomatous transformation of portal vein with or without the involvement of intrahepatic portal vein, splenic vein, or superior mesenteric vein. The most characteristic imaging manifestation is the formation of porto-portal collaterals that allow hepatopetal flow. Gradually there is organization and temporal evolution of thrombus with formation of portal collaterals termed "cavernoma" aiming to bypass the obstructed portal vein. Patients generally present in childhood with multiple episodes of variceal bleed and EHPVO is the predominant cause of paediatric portal hypertension (PHT) in developing countries.