Ultrasound diagnosis of extrahepatic portal vein obstruction in childhood. The sign of the subhepatic sponge-like mass.

Portal vein obstruction in childhood produces portal hypertension and hepatopetal collaterals surrounding the obstructed portal vein; this is the "cavernomatous transformation of the portal vein" which is a well defined angiographic entity. Clinically findings are the various manifestations of Banti's syndrome, especially splenomegaly and gastrointestinal bleeding. Ultrasonic diagnosis is possible on the associated findings of splenomegaly, normal liver, a subhepatic sponge like mass corresponding to the hepatopetal collaterals. These signs must be sought in the ultrasonic differential diagnosis of splenomegaly in pediatrics.