Facial nerve schwannomas

Abstract

Following vestibulocochlear and trigeminal nerve, facial nerve schwannomas (FNSs) are the third most frequent primary tumor that is associated with the cranial nerves [ 26 ]. FNSs are uncommon tumors, extremely slow growing, benign in the majority of cases, and frequently present without facial dysfunction. They can be mistaken for vestibular schwannomas. The tumor arises from Schwann cells in a focal manner as a solitary and well-encapsulated mass. They can arise at the cerebellopontine angle (CPA), internal meatus, geniculate ganglion, and peripheral nerves in the mastoid bone or in the muscle (Fig. 22.1). The most common sites are the geniculate ganglion and internal auditory canal. Malignant FNSs are extremely rare. This study reviews the surgical anatomy, the clinical presentations, the radiological diagnosis, the appropriate planning for the management, the surgical approaches, and the predictive outcomes of surgical management. Surgery is clearly indicated when the patient presents already facial nerve palsy. If the facial function is normal and the tumor is not compressing the brain stem, a conservative management is considered.