Cerebellar gangliocytoma presenting with hemifacial spasms: clinical report, literature review and possible mechanisms.

Cerebellar lesions have classically been considered not to cause epilepsy. However, previous reports have attributed seizures, beginning as hemifacial spasms to lesions of the cerebellar peduncles. We report an example of paroxysmal facial contractions associated with a cerebellar gangliocytoma. The seizures began on the first day of life and consisted of paroxysmal contractions involving the left orbicularis oculi, often the left forehead and lower facial muscles, sometimes accompanied by nystagmoid eye movements to the right and by head deviation to the left. Video-EEG monitoring showed only artifacts from muscle contractions. Magnetic resonance imaging showed a mass arising from the left superior cerebellar peduncle and partially occupying the fourth ventricle. The lesion was removed subtotally and partial seizure control was achieved. The neuropathological findings were consistent with a gangliocytoma. The literature in the association of cerebellar lesions with hemifacial spasms is reviewed and its possible mechanisms discussed.