HEPATIC STEATOSIS DUE TO CONGENITAL ABSENCE OF THE PORTAL VEIN

Abstract

Congenital portosystemic shunts are rare and known to cause various metabolic derangements. We report a child with congenital absence of the portal vein and portosystemic shunt who presented with hypergalactosemia, and was found to have other biochemical abnormalities as well as hepatocellular steatosis. A nine month old Caucasian girl was born at 38 weeks after an uncomplicated pregnancy. Her newborn metabolic screen on day of life 4 detected a high level of free galactose at 15 mg/dL (normal < 4). The RBC activities of the three major galactose metabolic enzymes were normal. She developed normally and achieved developmental milestones in a timely fashion. At 4 months the spleen was palpable 2 cm beneath the left costal margin. The elevated galactose level with normal enzymatic activity prompted investigation for evidence of a portosystemic shunt. A magnetic resonance angiogram of the abdomen demonstrated a small liver, with a virtually absent left lobe. The liver was of normal signal intensity, and without focal lesions. Mild splenomegaly was identified. No portal venous flow was identified either intra or extrahepatically. The superior mesenteric and splenic veins were patient, and drained via a large shunt to the left renal vein, and subsequently to the IVC. No other collaterals were identified. There was a small accessory retro-aortic left renal vein. Urine contained a trace amount of reducing substances. Serum chemistries revealed moderately elevated AST, ALT, and alkaline phosphatase. Blood ammonia was twice normal. Serum glucose, bilirubin, albumin, CBC, PT, and PTT were all normal. Subsequent evaluation at 8 months revealed an alpha-fetroprotein of 52.9 IU/ml (normal <6.4), a serum bile acid level of 3855 mcg/dl (normal <60), and hepatitis A and B serologies that were negative. The patient underwent liver biopsy at 9 months. The general hepatic architecture was well preserved, and the hepatocytes had normal size and orientation. There was depletion of glycogen and moderate diffuse microvesicular fatty change of hepatocytes. There was focal pericellular fibrosis with no evidence of necroinflammatory activity. Ultrastructural exam revealed occasional mitochondrial enlargement, but was otherwise normal. Peroxisomes were normal. This case illustrates histologic abnormalities of the liver, as well as biochemical abnormalities, that result from congenital absence of the portal vein and abnormal hepatic blood supply.