Abstract
We describe a patient with trigeminal neuropathy, involving the maxillary and mandibular divisions, caused by an arachnoid cyst in the cerebellopontine angle. A 47-year-old woman had abnormal sensation and numbness in the left upper lip and hypogeusis on the left after a common cold. She visited us because the symptoms did not disappear three months after the onset. Neurological examination revealed hypoesthesia limited to the maxillary and mandibular divisions of the left trigeminal nerve. Other abnormal neurological signs were not noted. The trigeminal neuropathy did not improve one year and five months after onset. MRI showed the presence of a space-occupying lesion in the left cerebellopontine angle. An arachnoid cyst compressing the left trigeminal nerve was found at surgery, and fenestration of the cyst was performed. The numbness of the lip and hypogeusis improved rapidly after the operation.
