Neurological paraneoplastic syndromes: an update

Purpose of review To describe recent advances in the diagnosis and treatment of paraneoplastic neurological syndromes (PNS). Recent findings PNS are rare complications of cancer caused by an immune cross- reaction between antigens expressed by tumor cells and neurons. The target of the immune attack can be an intracellular antigen or a cell- surface antigen. Although both types of autoimmunity are ` paraneoplastic', as indirectly triggered by the presence of a tumor, they profoundly differ in terms of clinical profile, pathogenesis and outcome. PNS associated with antibodies to intracellular antigens (icPNS) are characterized by relentless progression and poor response to treatment, because of rapid and permanent neuronal loss. PNS associated with antibodies to cell- surface antigens (csPNS) generally show favorable response to immune therapy and good functional outcome, as they result from reversible neuronal dysfunction. Summary The spectrum of paraneoplastic autoimmunity has dramatically expanded following the discovery of cellsurface antibodies. Novel antibodies are incessantly discovered, some of which have a solid association with cancer. As csPNS usually respond to immune therapy, the optimization of current treatment strategies should have high priority to improve therapeutic results and prevent relapses.