Canomad: report of a case with a 40‐year history and autopsy. Is this a sensory ganglionopathy with neuromuscular junction blockade?

Abstract

An 80-year-old man had a 40-year history of chronic sensory ataxic neuropathy and 11 years of relapsing/remitting episodes of rapid deterioration with perioral paresthesiae and weakness of bulbar, respiratory, and limb muscles. An immunoglobulin M (IgM) paraprotein was detected 12 years before death, and Waldenstrom macroglobulinemia was diagnosed on bone marrow biopsy 3 years before death. Chronic ataxic neuropathy with ophthalmoplegia, IgM paraprotein, cold agglutinins, and anti-disialyl antibodies (CANOMAD) was diagnosed. Comprehensive autopsy showed severe dorsal column atrophy and dorsal root ganglionopathy. A different pathology was identified in cranial and peripheral nerves, dorsal roots, and cauda equina, comprising infiltration of clonal B-lymphocytes within the endoneurium, perineurium, and leptomeninges. The autopsy provides evidence of the pathogenesis of the relapsing remitting component of CANOMAD, and we postulate that this may relate to the presence of clonal IgM anti-disiayl gangliosides secreting B-lymphocytes within nerves.