A Case of Chronic Demyelinating Neuropathy associated with IgG lamda Type Monoclonal Gammopathy of Undetermined Significance

ABSTRACT

Monoclonal gammopathy of undetermined significance(MGUS) is one of the monoclonal plasma cell disorder. According to the recent reports, polyneuropathy associated with MGUS may be treatable disease due to potential relationship between the monoclonal protein and immune-mediated nerve damage. It is reported that plasmapheresis is highly effective in the treatment of polyneuropathy associated with IgG type MGUS. We present 53-year-old male with slowly progressive motor weakness and sensory change since 1 year ago. Electrophysiologic studies were compatible with demyelinating neuropathy showing conduction block and temporal dispersion in upper and lower extremities. Abnormal arc against anti-lamda on serum immunoelectrophoresis and M-band in the gamma region on serum protein electrophoresis were shown. After the combined therapy of plasmapheresis (5 times) and steroid, clinical and electrophysiologic findings were markedly improved. We report a case of demyelinating neuropathy associated with IgG lamda type MGUS, which showed good response to combined therapy of plasmapheresis and steroid.