When to operate facial nerve schwannomas?

Abstract

Facial nerve schwannomas are rare, benign slow-growing tumors arising from the Schwann cell sheath of the facial nerve. A 60-year-old female presented with a mass in the left parotid region for 6 months. It was associated with Grade 6 left lower motor neuron facial palsy. Malignancy of the parotid gland associated with facial nerve involvement was suspected. However, high-resolution computed tomography temporal bone and magnetic resonance imaging done showed a soft-tissue density along the vertical portion of the facial nerve and into the parotid gland. The lesion was eroding the skull base and was found to be in direct contact with the jugular bulb. She underwent excision of the tumor by a modified Blair incision along with a cortical mastoidectomy. Tumor abutting the jugular bulb was removed through transmastoid approach. Facial nerve was transected during tumor excision. Postoperatively, gold implant was inserted. Facial schwannomas can arise from any segment of the nerve, from the cerebellopontine angle to the extratemporal peripheral portion. About 650 cases have been reported in the world literature. The best timing for surgery depends on facial and hearing function, size, and intracranial mass effect.