A case of the cerebellar form of progressive multifocal leukoencephalopathy in a patient undergoing hemodialysis

A 55-year-old female who had been on hemodialysis was admitted with cerebellar ataxia. She had been undergoing chemotherapy for myeloproliferative disease, and had started hemodialysis 10 months prior to admission. T2-weighted imagings on brain MRI showed demyelination in the cerebellum. Although it was not typical that the demyelinated region was limited to the cerebellum and the brain stem, progressive multifocal leukoencephalopathy (PML) was highly suspected because of the positive PCR finding of JC virus in her cerebrospinal fluid. The demyelinated region increased, and her symptoms worsened. Involuntary movement, dysarthria and dysphagia appeared. She died 10 months after onset due to repeated aspiration pneumonia. Autopsy demonstrated demyelination in the cerebellum and brain stem with JC viral protein in the same region. Thus, she was diagnosed with the cerebellar form of PML. Retrospective review of renal biopsy demonstrated an abundance of JC viral protein in the atrophic tubular epithelial cells. There have been some case reports of the cerebellar form of PML in hemodialysis patients in Japan. Although the cerebellar form has been reported to be rare, there is a possibility that the cerebellar form is not rare among hemodialysis patients. In this case, JC virus infection in the tubular cells may have been related to renal dysfunction. Although the relationship between JC viral infection and renal dysfunction is currently unclear, the pathological significance of JC viral infection in kidney needs to be elucidated.