Amyloid neuropathy and multiple myeloma. Ultrastructural and immunopathological study of two cases.

Report of 2 patients suffering from sensory peripheral neuropathy and multiple myeloma. In 1 case, peripheral neuropathy occurred several months before the appearance of multiple myeloma. A peripheral nerve biopsy exhibited numerous amyloid deposits within the endoneurium. Amyloid deposits have been estimated to occur in 15% of cases of multiple myeloma, but only 4 other detailed observations of amyloid deposits within the endoneurium have been reported in the literature. Other mechanisms might be involved since most peripheral neuropathies associated with multiple myeloma do not exhibit any amyloid deposits.