The authors report the case of a 4 month old child presenting with a congenital arteriovenous fistula of the left hepatic lobe, revealed by a melaena. Doppler ultrasonography and angiography showed a voluminous vascular malformation fed by a left hepatic artery and fistulized in the portal vein. The therapeutical approach was first palliative, by ligature of the left hepatic artery which proved unsuccessful and resulted in re-permeation of the malformation through a right hepatic artery. Two embolization procedures were then attempted, without success. A left hepatectomy was then performed to remove the malformation. The main event of outcome was the secondary occurrence of a portal cavernoma, with persistent splenic segmentary portal hypertension, and oesophageal varicosity. This case report is the occasion for a literature review on congenital arteriovenous fistulae in the portal region, and for a discussion on therapeutical modalities.