Progressive Multifocal Leukoencephalopathy as the First Manifestation of Occult Sarcoidosis Case Report and Review of the Literature

Introduction: Progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the central nervous system, is caused by reactivation of the JC virus. This disease is typically seen in individuals with known immune suppression. It has also been associated with other inflammatory conditions, such as sarcoidosis. Case Report: A 68-year-old woman without known immune suppression presented with mental status changes over several weeks. Brain biopsy and cerebrospinal fluid analysis led to the diagnosis of PML. On autopsy, she was found to have previously undiagnosed sarcoidosis. Conclusions: To our knowledge, this is the first published case of PML as the first manifestation of sarcoidosis in the absence of inflammatory hematologic involvement.