MYELOMA-ASSOCIATED POLYNEUROPATHY RESPONDING TO LENALIDOMIDE

In recent years, thalidomide has emerged as an important treatment for multiple myeloma, but its usefulness is limited by the occurrence of a toxic axonal polyneuropathy in many patients.1 Lenalidomide, a structural derivative of thalidomide with much lower neurotoxicity, is also effective in controlling myeloma, and has begun to be used as a first-line treatment.2 This article describes a patient with myeloma who presented with a severe demyelinating polyneuropathy that responded poorly to standard immunotherapy, but improved remarkably during treatment with lenalidomide. ### Case report. In March 2005, a 38-year-old woman developed numbness in her hands and feet and increasing limb weakness, worse in her arms. Within 6 months, she was unable to walk without support and could hardly feed herself. Nerve conduction studies performed elsewhere showed a mixed demyelinating and axonal polyneuropathy with markedly prolonged distal motor and sensory latencies and F wave latencies in many nerves (table). Needle EMG was normal in proximal and distal extremities. The spinal fluid contained 1 white blood cell per mm3 and protein 48 mg/dL. Serum immunofixation electrophoresis showed a monoclonal IgA-lambda paraprotein; total gamma globulin was 2.17 g/dL. Fasting blood glucose, antinuclear antibodies, rheumatoid …