Cervical dystonia associated with tumors of the posterior fossa.

Cervical dystonia was associated with posterior fossa tumors in three patients. The onset of dystonia paralleled the appearance of other focal neurologic signs. All patients had extraaxial tumors located in the cerebellopontine angle that were removed via suboccipital approaches. The tumors were identified as schwannomas arising from the glossopharyngeal nerve and from the vagus/accessory nerves; and a meningioma. Postoperatively, the cervical dystonia improved markedly during a period of 8 years in one patient, and it remitted completely within 1 year in another patient. In the third patient, cervical dystonia persisted. The combination of the clinical findings and the temporal relationship of their appearance suggest a causal association between the posterior fossa tumors and cervical dystonia in three cases. Possible pathogenic mechanisms are reviewed.