[Opsoclonus-myoclonus syndrome: a case report].

Opsoclonus-myoclonus syndrome is a rare disorder. We report a 44-year-old patient with opsoclonus associated with a cerebellar syndrome revealing a small cell lung carcinoma. The treatment with chemotherapy initially improved the clinical symptoms but these eventually recurred. Opsoclonus is a complex disorder of the ocular motility, characterized by irregular, continuous and chaotic eye saccades. When it is associated with other manifestations of the central nervous system (head myoclonus and ataxia), it constitutes a clinical picture known as opsoclonus-myoclonus syndrome. In adults, the most frequent causes are post-infectious, paraneoplastic and idiopathic. The symptomatic treatment is not defined, but the treatment of the underlying cause may improve the clinical features of this syndrome.