Malignant hepatic tumor occurring 10 yrs after a histocompatible sibling donor bone marrow transplantation for severe aplastic anemia

A 13-yr-old boy developed post-transplant liver tumor. At three yrs of age, this patient underwent a histocompatible sibling donor BMT for severe aplastic anemia, after a conditioning with antithymocyte globulin and cyclophosphamide. He became a HBV carrier after BMT. Stable mixed chimerism and mild thrombocytopenia, but no active hepatitis continued. At age 13, abdominal pain was a sign of massive tumor. Extremely high levels of α-fetoprotein indicated the clinical diagnosis of hepatoblastoma that might be the first report as post-BMT malignancy. The necropsy specimens revealed that the tumor was recipient cell-origin and showed the histopathological features of both hepatoblastoma and hepatocellular carcinoma. Prolonged mixed chimerism and hepatitis virus infection might induce a rare oncogenesis after non-irradiated conditioning.