Facial nerve schwannoma presenting as an occluding external auditory canal mass: a case report and review of the literature

Facial nerve schwannomas (FNS) are rare benign tumors, accounting for less than 1% of all intratemporal tumors. While they typically present with facial dysfunction, presentation as a mass occluding the external auditory canal (EAC) is exceedingly rare. This atypical growth pattern mimics common pathologies and poses a diagnostic challenge and a high risk of nerve injury during biopsy. A 30-year-old Middle Eastern male presented with progressive left-sided hearing loss and aural fullness. Physical examination revealed normal facial nerve function and a smooth, reddish, non-plsatile mass completely occluding the left EAC. Pure-tone audiometry showed a conductive hearing loss. High-resolution computed tomography demonstrated a well-defined soft-tissue mass in the EAC with smooth erosion of the posterior canal wall at the mastoid segment of the facial nerve. A nerve-sparing transcanal excision was performed. Histopathological examination confirmed a schwannoma with “ancient changes,” showing Antoni A and B areas and strong S-100 positivity. Postoperatively, facial nerve function remained normal, the EAC remained patent, and the patient showed no recurrence at 6-month follow-up. FNS should be considered in the differential diagnosis of any posterior EAC mass, even without facial weakness. Mandatory preoperative imaging is essential to avoid catastrophic nerve injury from the biopsy. In selected patients with complete external auditory canal occlusion, conductive hearing loss, or risk of secondary cholesteatoma, nerve-preserving surgical management may be considered. Long-term postoperative surveillance is recommended because of the slow-growing nature of these tumors.