Facial nerve schwannoma presenting as mixed hearing loss, tinnitus, and dizziness

Abstract

Introduction: Facial nerve involvement in skull base tumors is quite a common finding. However, facial nerve tumors are rare. Facial nerve schwannomas can be observed in 75% of facial nerve tumors. They are slowly growing, benign tumors that can arise from any segment of the facial nerve—from the cerebellopontine angle to the parotid gland. The most common clinical presentation in patients with an intratemporal schwannoma is a slowly progressing facial nerve dysfunction. Less frequently, a fluctuating or a sudden facial nerve weakness can be seen. Hearing loss, tinnitus, and dizziness can also be observed in facial nerve schwannomas. Hearing loss can be conductive, sensorineural or mixed, depending on the size and site of the tumor that can extend into the middle ear or erode the cochlea. Tumors of the internal auditory canal or of the cerebellopontine angle usually lead to a retrocochlear sensorineural hearing loss. Case Presentation: The authors present the case of a 19-year-old man suffering from a left-sided hearing loss, tinnitus and dizziness without any facial nerve dysfunction. Results: The patient underwent computed tomography (CT) scan and magnetic resonance imaging (MRI) with gadolinium to investigate the middle ear and internal auditory canal. A left facial nerve schwannoma, involving the geniculated ganglion, was diagnosed. Conclusion: Even if the most common symptoms of facial nerve schwannomas are facial nerve-related symptoms, we should always keep in mind that hearing-related and equilibrium-related symptoms can be the first presenting symptoms.