Neonatal hemifacial spasm and fourth ventricle mass.

Congential hemifacial spasm is a rare condition that is characterized by the occurrence of paroxysmal hemifacial contractions in neonates. We review the clinical, neurophysiological, neuroimaging, and histopathological findings, as well as the differential diagnosis, therapeutic approach, and outcome of all the described cases. Moreover, we report two new cases including the ictal video-electroencephalography recordings. Hemifacial spasm starts early in life, and is characterized by unilateral, involuntary, irregular tonic or clonic contractions of muscles innervated by the seventh cranial nerve. Hemifacial spasm is associated with eyelid blinking, and sometimes with breathing irregularities, hyperventilation, and/or other neurological manifestations (dystonic movements, nystagmus). Interictal and ictal video-electroencephalography did not reveal epileptiform abnormalities. In all cases, brain magnetic resonance imaging showed a mass involving the cerebellar peduncle, the cerebellar hemisphere, or the floor of the fourth ventricle. The semiology of the paroxysmal attacks is probably due to the activation of cranial nerve nuclei through intralesional hypersynchronous discharges, as shown by the intraoperative recordings and functional brain imaging described in the literature. We point out the importance of identifying such seizures in order to make an early diagnosis of the underlying cerebral lesion.