Progressive multifocal leukoencephalopathy. A case report.

Progressive multifocal leukoencephalopathy (PML) is a progressive demyelinating disease caused by JC virus, occurring in immunocompromised patients. In the HAART era, approximately 5% of the AIDS patients have been reported to develop PML. The clinical presentation of PML is quite variable because lesions may occur anywhere in the CNS white mater; the most common fi ndings are motor weakness, visual defects (e.g. visual blurring, diplopia), and incoordination. The most frequently affected regions are the cerebral hemispheres, followed by subtentorial lesions. The diagnosis of PML in an immunocompromised patient with evocative clinical picture of focal neurologic defi cits is made by demonstrating typical fi ndings on brain imaging studies and detection of viral DNA in CSF by PCR examination. Brain biopsy should be reserved for cases with suspicious white matter lesions on CT or MRI in which JC virus is not detected in PCR. Differential diagnosis should consider other primary as well as opportunistic infections of CNS, other demyelinating diseases (such as multiple sclerosis), vascular lesions (e.g. ischemic stroke, HIV vasculopathy), tumors (e.g. lymphoma) and HIV encephalopathy with secondary changes in white matter. The present paper describes the case of a HIV positive patient with clinical, biological and imaging fi ndings highly suggestive for PML, but negative PCR for JC virus DNA.