Huge facial nerve schwannoma extending into the middle cranial fossa without facial palsy: Case report

The facial nerve schwannoma is a rare tumor and it seldom extends into the middle cranial fossa. The typical clinical presentations are progressive facial paralysis and hearing disturbance. We report here a case of huge facial nerve schwannoma extending into the middle cranial fossa without facial palsy. A 50-year-old man presented with left hearing disturbance. Neurological examination on admission revealed no deficits except for sensorineural hearing loss. MRI demonstrated a cystic tumor extending into the middle cranial fossa from the petrous bone. CT of the temporal bone showed destruction of the surrounding bone around the geniculate ganglion and invasion of the tumor into the tympanic cavity and internal auditory canal. The intracranial tumor was totally removed and the operative specimen demonstrated that the tumor was a schwannoma. The patient was discharged without neurological deficit. The facial nerve schwannoma extending into the middle cranial fossa without facial palsy is rare and only 4 cases have been reported in the literature. The tumor origin was in the greater superficial petrosal nerve and geniculate ganglion. The symptom is conductive hearing loss caused by the tumor extending into the tympanic cavity. We should bear in mind that there is a also rare type of facial nerve schwannoma manifesting hearing disturbance alone.