[Progressive multifocal leukoencephalopathy (PML). Report of a case diagnosed by amplification of JC virus DNA from cerebrospinal fluid (CSF)].

We report a 54-year-old Japanese man who was diagnosed as progressive multifocal leukoencephalopathy (PML). He had been maintained on regular hemodialysis for 10 years. He was admitted to our hospital with chief complaints of visual disturbance and disorientation. On neurological examination, he was somnolent, and showed mild weakness in the right upper and lower limbs. Deep tendon reflexes were brisk on the right upper and bilateral lower limbs. Sensory examination revealed no abnormal findings. The cerebrospinal fluid (CSF) showed five mononuclear cells/mm3, protein 39 mg/dl and glucose 38 mg/dl. Brain MRI revealed multiple hyperintense lesions in T2-images, which were confined to the white matter of bilateral occipital and the left frontal lobes without an enhancement after gadolinium administration. Using polymerase chain reaction, we amplified the JCV regulatory region from the CSF of the patient. The amplified product contained a rearranged regulatory region that could have been generated from the archetype by deletion and amplification. PML was diagnosed on the basis of these findings. The patient died 7 months after onset of the symptoms. The diagnosis of PML was confirmed by the postmortem findings. The present case indicates that PCR of JCV from CSF is very useful for definitive diagnosis of PML.