Amyloid neuropathy in multiple myeloma and other plasma cell dyscrasias : a hypothesis of the pathogenesis of amyloid neuropathies

The development of amyloid neuropathy is an uncommon complication of multiple myeloma. The clinical, electrophysiological and pathological features of 3 such patients are described. The small fiber neuropathy in these 3 cases was similar to that in patients with primary amyloidosis and with the Andrade-type of familial neuropathy, and differed from the large fiber neuropathy which more commonly develops in patients with multiple myeloma. We advance the hypothesis that the absence of the blood-nerve barrier in the dorsal root and sympathetic ganglia allows the access of amyloidogenic proteins to these ganglia, and that these ganglia are the primary site of damage to the peripheral nervous system in the amyloid neuropathies.