Update on paraneoplastic and autoimmune disorders of the central nervous system.

Although the discovery of antineuronal antibodies has facilitated the diagnosis of paraneoplastic neurologic disorders, the recognition and treatment of these disorders remain a challenge. Some antibodies are more syndrome-specific than others, and some syndromes suggest a paraneoplastic etiology more frequently than others. Because some antineuronal antibodies may occur in cancer patients without paraneoplastic neurologic disorders, their detection does not necessarily imply that a neurologic disorder is paraneoplastic. Moreover, there is an emerging group of encephalitides that appear to be mediated by antibodies against cell surface or synaptic proteins, may occur with or without tumor association, and are responsive to treatment. This review analyzes the immune responses associated with paraneoplastic and nonparaneoplastic disorders of the central nervous system, and the main clinical features and response to treatment.