[Small-cell carcinoma of the lung with paraneoplastic cerebellar degeneration].

A 50-year-old man was admitted to our hospital because of slowly progressing ataxia. After the neurological examination and after observation of the clinical course, paraneoplastic cerebellar degeneration was suspected. Extensive examination revealed a malignant tumor in the right upper lobe of the lung. Immunoblotting with rat cerebellum revealed a 68 KDa protein in the patient's serum, which suggested that paraneoplastic cerebellar degeneration was caused by an auto-antibody. Anti-cancer drugs and radiation therapy were begun 4 months after the onset of symptoms. After 4 months of therapy, the lung cancer had shrunk, but the neurological symptoms had become more severe.