Abstract
Progressive multifocal leukoencephalopathy (PML) is a rare, often fatal, demyelinating disease of the central nervous system. The disease almost exclusively presents in immunosuppressed patients, such as those with acquired immunodeficiency syndrome, a hematopoietic malignancy, or a transplanted organ; it is extremely rare in patients without immunosuppression. We present a case of a 74-year-old female with radiographic and histopathological findings consistent with PML that possibly arose in the setting of Sjögren's-related vasculitis but no immunosuppression.