Case report: congenital absence of the portal vein associated with nodular hyperplasia in the liver.

Congenital absence of the terminal portion of the portal vein with visceral venous return to the suprahepatic inferior vena cava, a rare malformation, was demonstrated in an 18-year-old Japanese woman. She had nodular hyperplasia in the liver and a non-functioning pancreatic endocrine tumour. It is generally believed that reduction of portal venous flow causes atrophic changes and, subsequently, nodular hyperplasia occurs in a well-perfused area in the liver. However, the liver was not perfused by the portal vein in this case. It is suggested that nodular hyperplasia can occur without portal blood flow.