[Report of a case of small cell lung cancer associated with Lambert-Eaton myasthenic syndrome and subacute cerebellar degeneration--with a review of the Japanese literature].

We report a patient with small cell lung cancer associated with Lambert-Eaton myasthenic syndrome (LEMS) and subacute cerebellar degeneration (SCD). The patient was a 71-year-old man suffering from weakness of the limbs and a gait disturbance who developed limb ataxia and dysarthria one month after admission. Electrophysiologic studies confirmed the diagnosis of Lambert-Eaton myasthenic syndrome. Chest X-rays 2 months after admission revealed an abnormal shadow, and small cell lung cancer was diagnosed on the basis of biopsy specimens. Anti-voltage-gated calcium channel antibody was positive. Anti-Yo and -Hu antibodies were negative. The patient was treated by plasmapheresis and chemotherapy, which resulted in a transient improvement in the LEMS symptoms but not in the SCD. Fifteen cases of LEMS associated with SCD have been reported in the Japanese literature, and all were accompanied by small cell lung cancer. We discuss the frequency of association with LEMS and SCD and the effects of plasmapheresis and chemotherapy in both diseases.