Benign monoclonal gammopathy and peripheral neuropathy.

Peripheral neuropathy has been described in malignant plasma cell dyscrasias such as multiple myeloma and Waldenstöm's macroglobulinaemia. Since it is not known whether the neuropathy is related to the plasma cell disorder or is a paramalignant phenomenon, 21 consecutive out-patients with benign monoclonal gammopathy (BMG) were analysed for peripheral neuropathies. Eleven patients had noticed slight motor and/or sensory extremity symptoms. Clinical examination, electromyographic and electroneurographic studies of the upper and lower extremities were performed. In five patients all results indicated a neuropathy, six other patients had clinical signs of neuropathy and four additional patients had positive electromyographic and/or electroneurographic results compatible with neuropathy. There were no significant differences in haematological parameters between the group where all results indicated a neuropathy and the totally negative group or between the two groups with and without clinical neuropathy. Thus, the benign form of plasma cell dyscrasias seems also to be associated with mild clinical or subclinical peripheral neuropathy.