Paraneoplastic neurologic syndromes

Abstract

Paraneoplastic neurologic disorders are rare neurologic syndromes due to complications not attributable to direct invasion of the nervous system by the neoplasm, infections, or complications of cancer treatment. Many paraneoplastic neurologic disorders are associated with pathogenic anti-neuronal antibodies or T-cell responses to specific antigens. Expanded access to paraneoplastic antibody testing has led to early identification of autoantibodies but challenges remain in the interpretation of test results within the appropriate clinical context. Tumors commonly associated with CNS paraneoplastic neurologic disorders express neuroendocrine proteins, affect organs with immunoregulatory properties, or contain mature or immature neuronal tissue. Peripheral nervous system paraneoplastic neurologic disorders are more commonly associated with tumors that produce immunoglobulins. Disorders that do not conform to a classical paraneoplastic disorder or do not contain anti-neuronal antibodies are likely immune related or potentially triggered by immunotherapy. Improved detection of new autoantibodies, better characterization of paraneoplastic neurologic syndromes and their definitions together with earlier tumor identification has led to improved recognition and early initiation of treatment of these disorders. Challenges to treatment including variable treatment protocols, risks related to the underlying cancer, concurrent use of immunotherapeutic agents, and delays to initiation of treatment. This presentation will review classic concepts of these paraneoplastic disorders, recent clinical and immunologic diagnostic criteria, and treatment strategies for this diverse group of rare diseases.