Paraneoplastic neurological syndromes--diagnosis and management

Paraneoplastic neurological syndromes (PNS) are rare nervous system dysfunctions in cancer patients, which are not due to a local effect of the tumour or its metastases. PNS in adults are mainly associated with lung cancer, especially small cell lung cancer, lymphoma and gynaecological tumours. In some cases an overlapping of different clinical syndromes can be observed. Since autoantibodies directed against tumour and nervous system tissue can be observed, an autoimmune aetiology has been suspected in PNS patients. Currently, one group of patients exhibit surface-binding receptor or ion channel autoantibodies which are thought to be pathogenic and many of these patients respond well to immunotherapies. Another group of PNS is associated with highly specific autoantibodies directed against intracellular onconeuronal antigens. The latter group seem to be T-cell-mediated and do not respond well to immunotherapies. The childhood PNS, especially the neuroblastoma-associated opsoclonus-myoclonus syndrome also respond to immunosuppressive therapies, plasmapheresis and intravenous immunoglobulins. The current review summarizes recent developments in physiopathology, diagnosis and treatment of paraneoplastic neurological syndromes.