Portal-systemic shunting in a patient with normal portal vein pressures and histological evidence of idiopathic portal hypertension

Although idiopathic portal hypertension (IPH) is clinically characterized by portal hypertension and marked splenomegaly, we have experienced a case of spontaneous portal-systemic shunt without splenomegaly in whom the liver histology resembled IPH but with normal portal pressure. We admitted a 64 year old man who had suffered from hepatic encephalopathy for 2 years. Laparoscopy revealed a dark grey liver with a sharp edge and a concave surface. Examination of a liver biopsy specimen revealed peri-portal fibrosis consistent with IPH. A single, large, portal-systemic shunt was identified by percutaneous transhepatic portography. The shunt arose from the left gastric vein and flowed through the left renal vein into the inferior vena cava. No varices were identified. There were no morphological changes in the hepatic or portal veins. Portal vein pressure was normal. There was a slight difference between the portal pressure and the wedged hepatic vein pressure, suggesting a presinusoidal block. This case raises important questions concerning the aetiology of IPH and the relationship between portal hypertension and the development of collateral venous circulation.