Congenital absence of the portal vein: translated version.

Congenital portosystemic shunt (CPS) is classified into type I (congenital absence of the portal vein) and type II, depending on the presence or absence of the intrahepatic portal vein. Reports still exist on cases in which psychiatric diseases or mental retardation was diagnosed or cases in which diagnosis and treatment are not performed until severe pulmonary complications occur, indicating the need to recognize CPS. Herein, we reviewed epidemiology, etiology, classification, symptom, diagnosis, and treatment based on clinical view points of CPS. For clinical view points, classification according to (1) the presence or absence of the intrahepatic portal venous system (IPVS) and (2) the extrahepatic or intrahepatic of shunt sites, facilitates the understanding of pathophysiological conditions and is useful in selecting a treatment for symptomatic CPS. Radiological and pathological examinations are important in IPVS evaluations, and IPVS evaluations are currently essential to make diagnoses by portography with balloon occlusion and liver biopsy. Symptomatic CPS (hepatic nodular lesions, portosystemic encephalopathy, and pulmonary complications, etc.) is an indication of treatment by shunt closure, but an indication of treatment for asymptomatic CPS is the challenge going forward.