A 16-month-old boy presented with massive abdominal enlargement. Magnetic resonance imaging (MRI) revealed a liver tumor measuring 11 x 11 x 10 cm. Pulmonary metastases were detected by chest computed tomography. The diagnosis of a hepatoblastoma was made from the patient's age, the location of the tumor, and marked elevation of alpha1-fetoprotein (AFP). Chemotherapy according to the German Cooperative Pediatric Liver Tumor Study HB-94 was started, leading to a rapid and dramatic decrease in AFP levels. Despite an excellent response to chemotherapy, however, the abdominal distension increased. On a second MRI scan the tumor was unchanged in size, showing large areas of necrosis and cystic transformation. In addition, the patient acquired a cytomegalovirus infection with intractable diarrhea and severe pancytopenia. Since the patient's clinical course had worsened, the decision was made to alleviate the life-threatening tumor compression by an extended right hepatic lobectomy despite platelet-transfusion dependence and a white blood cell (WBC) count of only 300/microliter. Postoperative necrosis of the common bile duct necessitated a secondary resection with Roux-en-Y hepaticojejunostomy. The boy recovered quickly, and the white blood and platelet counts increased to normal values immediately after the first surgery so that chemotherapy could be finished after the postoperative recovery period. He is now in good condition without evidence of local or metastatic disease 1 year after the primary diagnosis.