[Facial nerve schwannomas: report of two cases]

Although schwannoma may arise from any true cranial nerve, it is well known that the acoustic and trigeminal nerves are frequent origins. Schwannomas of the facial nerve are rare. In this communication, two cases of facial nerve schwannoma arose from the horizontal portion are reported. Case 1. A 44 year-old male was admitted to our clinic complaining of left hearing loss and facial asymmetry. About three years prior to the admission, he first noticed left hearing disturbance which was gradually deteriorated and was transiently accompanied by left tinnitus during the progression. Then muscle spasm developed on the left eyelid which resolved spontaneously in a few weeks, then asymmetry of the face developed. Neurological examination on admission revealed left hearing loss and left peripheral facial palsy. As a result of neuro-otological examinations, left hearing impairment and left facial palsy were thought to be due to retrocochlear and suprageniculate lesions respectively. Plain skull radiograms and tomograms revealed marked destruction of left pyramis and enlarged internal auditory canal. Computed tomography of the brain showed low-density mass in the left middle fossa and defect of the tip of the left pyramis. After bolus injection of contrast material, peripheral portion of the middle fossa mass was enhanced non-homogeneously and enhanced mass extended to the posterior fossa. Left middle and posterior fossas were explored by carrying out a osteoplastic temporal flap and suboccipital craniectomy. A large extradural mass was noted to have filled the middle fossa which extended to the posterior fossa through destroyed pyramis and enlarged internal auditory canal. The tumor was removed subtotally.(ABSTRACT TRUNCATED AT 250 WORDS)