Background: Paraneoplastic neurologic syndrome (PNS) represents the remote effects of cancer on the nervous system. Diagnostic criteria for the syndrome were published by the PNS Euronetwork and form the basis of a database to collect standardized clinical data from patients with PNS. Objectives: To analyze various types of PNS, frequent tumor and antibody associations, clinical characteristics of individual syndromes, and possible therapeutic and prognostic strategies. Design: Prospective case series and database study. Setting: Twenty European centers. Patients: Patients were recruited from January 1, 2000, to December 31, 2008. Main Outcome Measures: Based on diagnostic criteria published by the PNS Euronetwork consortium, clinical characteristics of classic PNS and several other less well-characterized syndromes associated with cancer were assessed. Results: Data from 979 patients were analyzed, representing the largest PNS investigation to date. The findings elucidate the clinical evolution of paraneoplastic cerebellar syndrome according to the onconeural antibodies present, the heterogeneity and prognosis of dysautonomic disorders, and the clinical variability of paraneoplastic limbic encephalitis. Conclusion: The study results confirm that PNS influences oncologic patient survival. Tumors are the main cause of death, but some types of PNS (such as dysautonomia) have a poorer prognosis than malignant neoplasms. Arch Neurol. 2010; 67(3): 330-335
