An acute form of tyrosinemia type I with multiple intrahepatic mass lesions.

The acute form of tyrosinemia type I usually causes severe hepatocellular dysfunction. We report a 4-month-old infant with hepatosplenomegaly, ascites, and multiple intrahepatic mass lesions mimicking hepatoma. A marked increase of serum alpha-fetoprotein (97.6 micrograms/ml) and multiple small low-density lesions in the liver demonstrated by computed tomography suggested the presence of hepatoma. The liver specimens obtained at laparatomy showed mixed nodular cirrhosis with fatty metamorphosis. Serum levels of tyrosine (6.6 mg/100 ml) and methionine (5.9 mg/100 ml) were increased. Urinary organic acid analyses disclosed increased excretions of succinylacetone (1,330 mg/g creatinine) and delta-amino-levulinic acid (113.6 mg/g creatinine). Histological abnormalities and biochemical evidences led to the correct diagnosis. This case emphasizes the need for complete investigations of puzzling cases and warns against undue reliance on noninvasive imaging techniques.