[Osterosclerotic myeloma and polyneuropathy]

The peripheral neuropathy is a common complication in patients with osteosclerotic myeloma. The association with hepatosplenomegaly, lymphadenopathy and variable endocrine disturbances and skin changes constitute the POEMS syndrome. The pathogenesis of this syndrome is unclear, but the presence of M protein and elevated levels of interleukin-6 in the serum of patients, suggests an immunologic mechanism.

A 68 year old woman presented with a 2 year history of progressive weakness and paresthesias in both legs. Neurological examination revealed a sensorimotor polyneuropathy, involving predominantly the lower extremities. In addition to neurological findings, the patient had lymphadenopathy and skin hyperpigmentation. Serum protein immunoelectrophoresis revealed a peak of monoclonal IgA lambda paraprotein. Radiographic examination disclosed multiple osteosclerotic lesions. Electrophysiological evaluation showed a severe axonal and demyelinating sensorimotor polyneuropathy. Biopsy of sural nerve revealed demyelination and axonal degeneration. Axillary lymph node biopsy were consistent with giant lymph node hyperplasia. Interleukin-6 serum levels were normal.

The POEMS syndrome or Crow-Fusake syndrome is a rare multisystem disorder often associated with osteosclerotic myeloma. A severe demyelinating sensorimotor polyneuropathy frequently constitutes the chief complaint. These patients have a polyneu-ropathy which resembles idiopathic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and the electrophysi-ological studies are essential in the diagnosis. The pathogenesis has not been explained. Presumably, the plasma cells secrete an immunoglobulin or another substance that is toxic to peripheral nerves. Interleukin-6 is implicated in the pathogenesis of this disease.