Correlating Pathology With the Clinical Symptoms of Methotrexate-induced Leukoencephalopathy in a Child With Relapsed T-cell Acute Lymphoblastic Leukemia

Intrathecal and systemic methotrexate (MTX), as well as cranial radiation, are effective modalities to prevent central nervous system relapse in childhood acute lymphoblastic leukemia. Leukoencephalopathy is a well-described adverse effect of MTX therapy and is associated with a wide range of neurological sequelae. Most recent studies of MTX-induced leukoencephalopathy have focused exclusively on imaging findings, particularly magnetic resonance imaging. Here we report a case of severe MTX-induced leukoencephalopathy with unique magnetic resonance imaging findings and pathologic correlation from a brain biopsy taken during a period of active neurological symptomatology.