Progressive multifocal leukoencephalopathy secondary to rituximab-induced immunosuppression and the presence of John Cunningham virus: a case report and literature review.

We present the case of a 60-year-old man who developed subacute neurologic changes, in the setting of stage III non-Hodgkin's follicular lymphoma, and was treated with induction chemotherapy, followed by a year of maintenance rituximab. Magnetic resonance imaging of the brain with gadolinium was pathognomonic for progressive multifocal leukoencephalopathy (PML). He was treated with sequential plasmapheresis and intravenous immunoglobulin with clinical improvement. A literature review of the diagnostic workup of rituximab-induced PML was undertaken. This case and the literature review demonstrate the important role of magnetic resonance imaging of the brain in diagnosis and follow-up of rituximab-induced PML. Specific radiologic features in combination with cerebrospinal fluid can be diagnostic and avoid the morbidity and mortality of a diagnostic brain biopsy. Plasmapheresis and intravenous immunoglobulin have a therapeutic role and demonstrate symptom improvement and disease control. Follow-up imaging in combination with clinical response is important in demonstrating a treatment response.