Asymptomatic progressive multifocal leukoencephalopathy: a case report and review of the literature.

Our case report illustrates that early detection of asymptomatic progressive multifocal leukoencephalopathy and its subsequent treatment resulted in a benign clinical course. In consideration of the additional small number of cases of asymptomatic progressive multifocal leukoencephalopathy that have been reported, we conclude that routine magnetic resonance imaging surveillance is important for patients with multiple sclerosis who are at high risk for developing natalizumab-associated progressive multifocal leukoencephalopathy.