Progressive multifocal leukoencephalopathy in a child with acquired immunodeficiency syndrome (AIDS).

Progressive multifocal leukoencephalopathy is a rare viral-induced demyelinating disease associated to immunodeficiency. A 10-year-old boy with AIDS is reported, who developed subacute cerebellar signs and symptoms with multiple cranial nerve involvement and dementia. A computed tomography scan revealed a focal nonenhancing area of low attenuation in the cerebellum. On magnetic resonance imaging high signal lesions in T2 weighted sequences were shown. The biopsy of one of those lesions showed the typical histological findings of progressive multifocal leukoencephalopathy. It seems important to consider this diagnosis in children with AIDS who present with progressive neurological features.