Trigeminal neurinoma with unusual presentation. Report of a case with trigeminal somatosensory-evoked response.

A patient with trigeminal neurinoma, presenting unusual symptoms, is described. There was no trigeminal sensory or motor deficit. The only presenting symptoms were unilateral abducens nerve paresis and alternating hemiplegic episodes. The trigeminal somatosensory-evoked response was normal before surgery. After complete removal of the tumor from both the posterior and middle cranial fossae, severe trigeminal sensory deficit ensued, accompanied by impairment of the evoked response. Improvement of the trigeminal nerve function could be predicted by significant changes in a repeat trigeminal sensory-evoked response obtained 2 months after the operation.