Mesial temporal sclerosis associated with methotrexate-induced leukoencephalopathy.

Mesial temporal sclerosis is a common form of symptomatic, localization-related epilepsy in children and adolescents, but its occurrence with acute lymphoblastic leukemia is rare. We present clinical records and neuroimaging results of a 13-year-old patient with acute lymphoblastic leukemia who developed recurrent partial seizures after an episode of leukoencephalopathy thought to be caused by methotrexate. Neuroradiologic images revealed hippocampal abnormalities consistent with the findings of mesial temporal sclerosis. Mesial temporal sclerosis was not previously reported in acute lymphoblastic leukemia patients with methotrexate-induced leukoencephalopathy. However, our case suggests that the pathogenesis of mesial temporal sclerosis may be associated with methotrexate-induced neurotoxicity.