Although reports of hypoplasia or absence of the liver of left lobe are not few, descriptions of the intrahepatic vessels are rare but valuable for discussion of the pathogenesis. The present report demonstrates a case of the left surgical lobe hypoplasia that is characterized by 1) the scar-like lobe with few parenchymal tissue and dilated bile ducts, 2) no Spiegel's lobe with the portal vein stuck to the inferior vena cava, 3) unusual configurations of the right hepatic vein and the 8th segmental portal vein branch, 4) the hepatic groove on S8, and 5) the trifurcation pattern of the portal vein primary division. According to the macroscopic and histological observations, we hypothesized that the secondary abnormal peritoneal fusion occurred in utero and/or during the postnatal growth, and that it involved the left portal vein and other adjacent structures, resulting in severe atrophy of the left surgical lobe.