Diffuse Large B-Cell Lymphoma Presenting as an Unusual Paraneoplastic Neurologic Syndrome Affecting the Central and Peripheral Nervous Systems

A 68-year-old man presented with a two-week history of ascending, symmetric, sensory neuropathy concerning an acute inflammatory demyelinating polyneuropathy that briefly responded to intravenous immunoglobulin (IVIg) therapy. The initial workup was negative for acquired causes. After three months of poor response to standard therapies, he was hospitalized for severe disability, unintentional weight loss, and additional, unexplained neurologic symptoms including cerebellar ataxia, dysarthria, and muscle twitching. Positron emission tomography revealed hypermetabolism isolated to the bone marrow. Bone marrow biopsy confirmed the diagnosis of diffuse large B-cell lymphoma (DLBCL). Due to rapidly worsening performance status, plasmapheresis was initiated prior to treatment with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy. His symptoms initially improved following plasmapheresis and resolved with chemotherapy. One year following treatment, he remains in complete remission. This case describes a unique paraneoplastic neurologic syndrome involving the central and peripheral nervous system that responded well to plasmapheresis and systemic chemotherapy.