Abstract
A 62-year-old woman was admitted to our hospital because of a liver tumor after undergoing resection for rectal cancer. CT showed a tumor 5 cm in diameter in the right lobe of the liver and an unusual vessel arising from the hepatic hilus into the liver. Under a diagnosis of liver metastasis from rectal cancer, a celiotomy was performed. Intraoperative ultrasonography revealed that the portal branch of the medial segment (P4) independently bifurcated from the portal trunk, and that an unusual branch (P8*) arose from the hepatic hilus along the right side of the middle hepatic vein into the liver. The portal branch of the lateral segment did not connect with P4, but with P8*.A right hepatic lobectomy with a preservation of the P8* was performed. Microscopically, the portal vein showed a thin venous wall and numerous branches. Retrospective study of computed tomography, the portal trunk showed prepancreatic retroduodenal type which indicated some relation to an anomalous branching of the portal vein. At a hepatectomy with an anomalous portal branching, a careful observation is essential before and during an operation.
