Anticerebellar antibodies in serum and cerebrospinal fluid of a patient with oat cell carcinoma of the lung and paraneoplastic cerebellar degeneration.

A 56-year-old man was seen with subacute cerebellar degeneration and was found to have oat cell carcinoma of the lung. Antibodies to cerebellar Purkinje cells and granule cells were detected in both serum and cerebrospinal fluid (CSF), and intrathecal antibody synthesis was suggested by serum CSF antibody ratios, CSF IgG index, and CSF IgG synthesis rate. The patient's condition improved slightly with plasmapheresis, corticosteroids, and therapy of his underlying tumor, but he continued to exhibit a severe cerebellar deficit until his death more than one year later. Paraneoplastic cerebellar degeneration may be accompanied by synthesis of anticerebellar antibodies, both systemically and within the central nervous system.