Chorea and related movement disorders of paraneoplastic origin: the PNS EuroNetwork experience.

Chorea and other movement disorders are rarely described as paraneoplastic. The aim of this study was to describe 13 patients with paraneoplastic chorea and dystonia collected by the members of the paraneoplastic neurological syndrome (PNS) EuroNetwork and to review 29 cases from the literature. We analyzed neurological symptoms, severity of the neurological syndrome, delay in neurological diagnosis, associated cancer, oncological and neurological treatments received, and outcome. Eleven (1.2%) out of 913 patients with PNS were identified in the EuroNetwork register. Two more patients not included in the register were added. The overall population consisted of 13 patients with a median age of 75 years (range 49-82 years). In most patients, the movement disorder was classical choreoathetosis with symmetric involvement of the trunk, neck, and limbs. A minority of patients presented unilateral chorea, dystonia, and orobuccal dyskinesia. Associated symptoms, as polyneuropathy, encephalitis, psychiatric disturbances, or visual defects, were often present. The movement disorder usually had a subacute course. The most frequently associated cancer was small cell lung cancer (SCLC). Lymphoma, bowel, or kidney cancers were also reported. CV2/CRMP5 was the most frequently associated antibody, followed by Hu. Hyperintense lesions of the basal ganglia on T2-weighted images were seldom observed. Response to cancer therapy was observed in a minority of patients, but survival was short (17 months). As in other neurological diseases, movement disorders should also be suspected as paraneoplastic when they develop subacutely in older patients (usually over 50) and often in the presence of other ancillary neurological symptoms.