A magnetic resonance abnormality correlating with permeability of the blood-brain barrier in a child with chemical meningitis during central nervous system prophylaxis for acute leukemia.

Chemical meningitis developed in a boy with acute lymphoblastic leukemia during central nervous system (CNS) prophylaxis. Cerebrospinal fluid examination showed pleocytosis and a high protein level. There were no malignant cytological findings. Calculated permeability of albumin across the blood-brain barrier (BBB) was more elevated than that of immunoglobulin or alfa2-macroglobulin. Magnetic resonance imaging (MRI) revealed diffuse pachymeningeal enhancement without any intracerebral lesion. Subsequent CNS prophylaxis was postponed. CSF findings and BBB permeability returned to normal, correlating well with the decrease of MRI abnormality.