A case of idiopathic portal hypertension after renal transplantation

A case of idiopathic portal hypertension (IPH) developing after renal transplantation is reported. A 33-year-old Japanese male who had undergone renal transplantation 8 years previously was transferred to our hospital because of hematemesis from ruptured esophageal varices. He had no history of any liver disease before the renal transplantation, but had a history of receiving blood transfusion. Abdominal computed tomography (CT) and ultrasonography revealed marked splenomegaly and collateral channels, but no obliteration which might cause portal hypertension in the hepatic or portal vein. No findings suggestive of hepatitis or liver cirrhosis were found either macroscopically on laparoscopy or by liver biopsy. Light microscopic study of the liver biopsy specimen showed mild periportal fibrosis, inconspicuous portal branches in the most peripheral tracts, but no pseudolobule formation or piecemeal necrosis. However collagen deposition was found in the perisinusoidal space and partly in intercellular space on electron microscopy. We consider that the development of portal hypertension in this case is responsible for the collagen deposition, which may be related to the administration of azathioprine after renal transplantation. There are few reports on IPH after renal transplantation, and it is stressed that a lower amount of azathioprine than previously reported may induce IPH under such conditions.