Hypogenesis of right hepatic lobe accompanied by portal hypertension: case report and review of 31 Japanese cases.

We report a rare case of hypogenesis of the right lobe of the liver with portal hypertension and a review of 31 cases of agenesis or hypogenesis of the right hepatic lobe reported in Japan. A 74-year-old man consulted our hospital for further examination after a mass screening for gastric cancer. On physical examination liver enlargement was palpable, but liver function tests were normal. Abdominal ultrasonography, computed tomography, technetium-99m liver scintigraphy, and endoscopic retrograde cholangiopancreatography revealed a small right hepatic lobe and moderate splenomegaly, in contrast to a hypertrophic lateral segment of the left hepatic lobe, as well as ectopic dislocation of the gallbladder. Endoscopic examination revealed esophageal varices, indicating portal hypertension. Abdominal angiography demonstrated mild shunt flow between the hepatic artery feeding from the gastroduodenal artery and the portal vein. A biopsy specimen taken from both lobes of the liver showed normal liver tissue histologically. Based on these findings, we made a definite diagnosis of hypogenesis of the right lobe of the liver with portal hypertension. The present case appears to be the first such case accompanied by portal hypertension reported in Japan.