Aneurysm of the intrahepatic branch of the portal vein. Report of two cases.

Two patients in whom real-time ultrasonography and percutaneous transhepatic portography or the venous phase of the arteriogram of the superior mesenteric artery demonstrated a localized saccular dilation of a peripheral branch of the portal vein are described. One patient subsequently died, and autopsy confirmed the diagnosis. A hypoechoic lesion continuous with a branch of the portal vein seems to be the characteristic sonographic picture. Radiologic evidence for portal vein aneurysm was obtained in only 2 of 300 patients with portal hypertension in whom percutaneous transhepatic portography was performed, and in 2 of 3000 patients who visited our unit and in whom ultrasonography for the liver was performed. Thus, aneurysm of the intrahepatic portal vein does occur, but very rarely.