Peripheral neuropathy in dysglobulinemic states

Peripheral neuropathy is a well known complication of multiple myeloma, macroglobulinemia, and other dysglobulinemic states. Neuropathy may be the first manifestation in these diseases. Deposits of amyloid around or within peripheral nerves can be the pathophysiological mechanism of the neuropathy. Two patients suffering from peripheral neuropathy are described. The first developed a severe sensory motor neuropathy against a background of monoclonal gammapathy. Kappa chain was demonstrated by serum immunoelectrophoresis without any other findings of multiple myeloma or macroglobulinemia. Light chain kappa was found within the endoneurium as well as in the perineurium by immunofluorescence, without any evidence of amyloid deposits. The second patient had amyloid tumors in both antecubital fossae, causing entrapment neuropathy with laboratory evidence of multiple myeloma. Sections of the amyloid tumors showed kappa chains by the immunofluorescence technique. Evidence of kappa chain deposits and amyloid tumors are two extremes of the possible pathological spectrum in this peculiar form of neuropathy.