Progressive multifocal leukoencephalopathy following treatment with bendamustine and rituximab

A 66-year-old female developed progressive multifocal leukoencephalopathy (PML) 17 months after treatment with bendamustine and rituximab chemoimmunotherapy. During her evaluation for PML, she was found to have a CD4 count of 176 cells/μL (reference range 492-1740). The patient demonstrated spontaneous recovery of symptoms that occurred in parallel with recovery of the CD4 counts. While PML is associated with rituximab therapy, the timing and patients' clinical course are atypical, raising the possibility of a previously unreported association with bendamustine therapy.