Paraneoplastic Syndromes

Paraneoplastic neurological syndromes represent indirect complications of certain malignancies, often due to neurological autoimmunity. These are rare, but important, entities, affecting less than 0.1% of patients with cancer. Clinical manifestations can be quite varied and multifocal. Several distinct clinical syndromes are recognized, including sensory neuronopathy, cerebellar degeneration, limbic encephalitis, and Lambert-Eaton syndrome. These disorders are usually associated with a subacute onset and significant disability. Typically, the neurological presentation antedates the diagnosis of malignancy, and the cancer, when found, tends to be localized and responsive to treatment. Diagnosis depends on clinical suspicion, serology for paraneoplastic antibodies, and a focused search for cancer. Imaging studies are important in the diagnosis of central nervous system disorders and also for the detection of occult malignancy. Management of these disorders includes treatment of the cancer (if identified) as well immunotherapy.