Paraneoplastic neurologic syndromes

Paraneoplastic neurologic syndromes (PNS) are remote, nonmetastatic complications of systemic cancer. Clinically they are characterized by subacute, progressive neurologic deficits that usually result in profound disability and eventually death. PNS may be present as long as 2 to 4 years before diagnosis of the associated tumor, but it can develop after diagnosis or when the cancer is thought to be in remission. Serum and cere-brospinal fluid (CSF) from many patients with PNS contains antineuronal antibodies which recognise antigens within the tumor. This suggests that PNS are autoimmune disorders in which the immune response, elicited by the patient’s tumor, cross-reacts with specific neuronal proteins.