Tyrosinemia type 1: metastatic hepatoblastoma with a favorable outcome

The clinical course of tyrosinemia type 1 is characterized by acute liver failure in infancy or chronic liver dysfunction and renal Fanconi syndrome in late-presenting cases. Dietary treatment may improve liver function but does not prevent the development of hepatocellular carcinoma (HCC) in late childhood. A new treatment strategy that uses 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), which prevents the production of toxic/carcinogenic metabolites, has dramatically changed the outcome of the disease by reducing the occurrence of liver cancer, especially in patients who start this treatment before the age of 2 years. We report here the case of a patient with a diagnosis of tyrosinemia type 1 at 5 months of age who was treated with NTBC and dietary restriction and in whom a liver neoplasm with lung metastases, histologically determined to be HCC, was found at the age of 15 months. A conservative approach that consisted of chemotherapy and partial hepatectomy resulted in a 12-year disease-free period. The excellent postchemotherapy course, in sharp contrast to the expected course of HCC, led to histologic reevaluation with reclassification of the neoplasm as hepatoblastoma. A diagnosis of hepatoblastoma would no longer be a mandate for a liver transplant for patients with tyrosinemia type 1 undergoing NTBC treatment. We encourage clinicians to perform more accurate evaluation of liver histology, because a neoplastic mass in a child with tyrosinemia type 1 is not the same as HCC.