[Progressive Multifocal Leukoencephalopathy Associated with HIV Infection Diagnosed by Brain Biopsy with Repeated Negative PCR Testing of CSF JC Virus DNA].

A 36-year-old man with human immunodeficiency virus (HIV) infection was admitted to our hospital due to progressive ataxia. Brain MRI demonstrated high-signal intensity in the white matter of the right parietal lobe and left cerebellar hemisphere on T2-weighted images. Despite antiretroviral therapy, as his clinical symptoms worsened and MRI lesions gradually increased with the appearance of gadolinium-enhanced lesions, immune reconstitution inflammatory syndrome by progressive multifocal leukoencephalopathy (PML) associated with HIV infection was suspected. However, JC virus (JCV) in the cerebrospinal fluid (CSF) was undetectable by DNA PCR twice. Therefore, biopsy of the right parietal lobe was performed. JCV DNA was detected by PCR using the biopsy sample. JC viral protein was also identified by immunohistochemistry. Brain biopsy should be considered for the clinical diagnosis of PML when CSF JCV is negative on repeated DNA PCR. (Received September 20, 2019; Accepted January 14, 2020; Published May 1, 2020).