Clinical and electrophysiological studies were performed on 23 subjects with multiple myeloma. Three subjects had clinical and electrophysiological evidence of a peripheral neuropathy, and six subjects without clinical evidence of a neuropathy had a diffuse impairment of motor and sensory conduction, an overall incidence of 39%. Sural nerve biopsies were examined from five affected subjects. The primary pathological lesion was found to be axonal degeneration resulting in a loss of both myelinated and unmyelinated fibers.
Walsh JC. The Neuropathy of Multiple MyelomaAn Electrophysiological and Histological Study. Arch Neurol. 1971;25(5):404-414. doi:10.1001/archneur.1971.00490050038003