Multifocal motor neuropathy with conduction block associated with metastatic lymphoma of the nervous system.

Peripheral neuropathies occur in 5% of patients with Non-Hodgkin Lymphoma and represent the effects of therapy, direct compression or nerve infiltration by tumor, or paraneoplastic effects. Multifocal motor neuropathy with conduction block (MMNCB) is a rare demyelinating disorder of unknown etiology characterized by progressive, distal, asymmetric weakness mostly of the upper limbs with minimal or no sensory loss. We report a patient, who developed MMNCB at the time of isolated CNS relapse from a diffuse large B-cell lymphoma. Marked neurological improvement was achieved using intravenous immunoglobulin treatment. To our knowledge, MMNCB has thus far not been described as part of the spectrum of lymphoma-related peripheral neuropathies.