Simultaneous hepatoblastoma in identical male twins. Identical male twin infants who in 1987 presented with hepatoblastoma at the age of 7 months are reported. Twin B was admitted for investigation due to enlarged liver and spleen. He was found to have an inoperable hepatoblastoma of fetal type and was treated with chemotherapy and local irradiation. However, 7 months after the chemotherapy the tumor recurred. The asymptomatic twin A was examined because of the known familial cases, and he proved to have an identical tumor. He was successfully radically operated on and 2 years after the chemotherapy is still doing well with no evidence of tumor. As the mother and the maternal grandmother had polyps in the colon, quite probably the hepatoblastomas of the twins were associated with familial adenomatous polyposis. 