Intracranial lymphoblastic sarcoma mimicking a primary brain tumor.

A lymphoblastic sarcoma mimicked a medulloblastoma in a 15-year old girl with a history of acute lymphoblastic leukemia diagnosed at age of 2 years. There was no evidence of leukemic infiltration in the brain during the 13-year latency period after the original diagnosis. She had received both prophylactic intrathecal methotrexate and central nervous system irradiation. This case emphasizes the need to consider leukemia as the cause of a 'brain tumor' in any patient that has a prior history of leukemia, regardless of the tumor manifestations or the remission duration of the leukemia.