Prolonged meningeal leukemia. Occurrence during hematologic remission of acute myeloblastic leukemia

MENINGEAL leukemia accounts for initial relapses in many patients with acute lymphocytic leukemia.1Systemically administered chemotherapy does not penetrate the blood-brain barrier, and leukemic cells in this sanctuary can multiply uncontrolled. With the introduction of prophylactic cranial irradiation and the intrathecal administration of methotrexate and other cytotoxic agents, a definite reduction of meningeal leukemia has occurred.2 In cases of acute myelocytic leukemia, meningeal leukemia occurs less frequently. Weil and co-workers,3in a study of 836 cases of acute myelocytic leukemia, found meningeal leukemia in only 48 instances (5.7%). Seligman et al4also noted a similar incidence in their review. Because of this low incidence, prophylactic treatment for meningeal leukemia is not widely used in acute myelocytic leukemia. The most frequent form of relapse in this type of leukemia after successful remission induction is hematologic. Improved remission induction due to better chemotherapy and immunotherapy5and longer