Eosinophilic meningitis preceding meningeal relapse in a child with acute lymphoblastic leukemia: abnormal nucleotide content of eosinophils.

A case of eosinophilic meningitis 2 months before the appearance of lymphoblasts in the cerebrospinal fluid is described in a child with acute lymphoblastic leukemia (ALL). The peripheral blood showed no simultaneous eosinophilia. The child was successfully treated for her CNS relapse, and complete remission was easily obtained. The eosinophils and lymphoblasts disappeared quickly after the administration of intrathecal methotrexate. However, 3 1/2 years later hypereosinophilia developed in the blood and bone marrow, heralding bone marrow relapse. Simultaneously, meningeal relapse was diagnosed and this time the cerebrospinal fluid showed a mixture of lymphoblasts and eosinophils. Treatment was reinstituted and complete remission was again obtained. Analysis of the blood eosinophils showed abnormal nucleotide patterns. Similar patterns were previously found in the lymphoblasts from other ALL patients.