Surgery is indicated for intratemporal facial nerve schwannoma with severe facial palsy, but even if nerve transplantation or a hypoglossal-facial nerve anastomosis is performed after complete tumor resection, only insufficient resolution of the facial palsy is obtained. Follow-up with imaging is usually undertaken for cases of intratemporal facial nerve schwannoma without facial palsy. Herein, we present a case of intratemporal facial nerve schwannoma without facial palsy which was followed up for 10 years using imaging studies.

A 59-year-old male patient presented with the chief complaint of right hearing loss. On examination, the right tympanic membrane was not visible due to the presence of a very large tumor in the right external acoustic meatus. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed that the tumor in the mastoid segment of the facial nerve canal had spread outside the external acoustic meatus, damaging its posterior wall. Moreover, the tumor extended to the parotid gland, forming a dumbbell-like shape. There was no facial paralysis, although an audiogram indicated slight, right hearing loss. Based on the imaging findings, the patient was diagnosed as having intratemporal facial nerve schwannoma. His symptoms and tumor size were monitored by MRI yearly. There was no facial palsy, although the tumor increased gradually in size in the external acoustic meatus, parotid gland, and the mastoid segment of the facial nerve canal. His right conductive hearing showed only moderate deterioration.

The basic therapy for intratemporal facial nerve schwannoma is nerve transplantation after complete tumor resection or nerve-sparing stripping. However, both methods have disadvantages, and neither is sufficient to resolve the facial palsy completely. Thus, in the absence of facial palsy, surgery is not indicated in cases of intratemporal facial nerve schwannoma, unless malignancy or intracranial tumor invasion is suspected. The present case required careful follow-up despite the absence of facial palsy, because of the steady growth of the tumor.