Medulloblastoma as a secondary malignancy after radiotherapy-free treatment for acute lymphoblastic leukemia

Malignant brain tumors have been reported to occur in survivors of childhood acute lymphoblastic leukemia (ALL) more frequently than in the noncancer control population. The strongest risk factor seems to be cranial radiotherapy, used as central nervous system (CNS) prophylaxis. We report the case of a 9-year-old girl affected with metastatic medulloblastoma that developed 6 years after a diagnosis of acute lymphoblastic leukemia. CNS prophylaxis for ALL consisted of intrathecal methotrexate plus cytarabine (20 administrations) and 4 courses of high-dose methotrexate (5g/m2). No prophylactic cranial radiotherapy was administered. The child, in first complete remission, was well until the occurrence of a second tumor. She was treated for medulloblastoma with craniospinal radiotherapy and chemotherapy. At present, she is alive but with disease. As the unusual association of these 2 malignancies in this patient, the p53 status was investigated using FISH analysis by specific DNA probe; no p53 mutation was detected.