[A case of mononeuritis multiplex associated with type I (monoclonal) IgG kappa cryogloblinemia]

We here reported a fifty-three year-old woman with mononeuritis multiplex, associated with type I cryoglobulinema induced IgG kappa MGUS (monoclonal gammopathy of undetermined significance). She first experienced numbness in the extremities, that showed stepwise deterioration for several weeks. The nerve conduction study revealed axonal neuropathy, and laboratory examination detected type I cryoglobulinema. The sural nerve biopsy demonstrated with severe axonal degeneration with focal accentuation, lacking any inflammatory response. Single cryofiltration definitely stopped the progression of the symptoms. The prompt clinical response to the removal of cryoglobulin, without the administration of anti-inflammatory drugs, confirmed the direct etiological correlation between type-1 cryoglobulin and the neuropathy, and may favor ischemic, rather than inflammatory nature of this rare type of neuropathy.