Seizures and their outcome in progressive multifocal leukoencephalopathy.

Seizures are not expected in progressive multifocal leukoencephalopathy (PML), a condition considered to be restricted to the white matter. Review of medical records of 89 patients with possible or proven PML showed an 18% prevalence of seizures. Seizures usually responded well to treatment and did not affect survival. The presence of PML lesions immediately adjacent to the hemispheric cortex was the only risk factor associated with seizures in this population.