Facial Nerve Schwannomas Presenting as Occluding External Auditory Canal Masses

Introduction: Facial nerve schwannomas are rare tumors of the lateral skull base. Treatment options for these tumors include observation, stereotactic radiation, and microsurgical removal. Erosion of the bony posterior canal from the descending segment of an entirely intratemporal tumor is an unusual growth pattern. With tumor in the external canal, a unique set of clinical challenges arises. We discuss the management strategies for facial schwannomas with this unusual growth pattern in patients of two disparate ages.

Setting: The study was conducted at a tertiary care academic medical center.

Methods: Records were reviewed for two patients with facial nerve schwannomas eroding into the external auditory canal (EAC).

Results: Two patients are presented, a 69-year-old woman and an 11-year-old boy, with facial nerve schwannomas showing atypical growth patterns of erosion through and occlusion of the EAC. Both patients had normal facial function (HB I/VI) and had tumors that medially entrap squamous debris, thus forming canal cholesteatomas. They would remain free of infection, however, if the keratin accumulation was regularly débrided. Stereotactic radiation, while possibly controlling future tumor growth, would not relieve the anatomic obstruction in the EAC. The 69-year-old patient has been managed successfully for 3 years with regular débridement, no tumor growth, normal facial function, and no other symptoms. The 11-year-old had a 30-dB conductive hearing loss. Due to his young age and anticipated future complications, surgery with either dissection of the tumor from the main facial nerve trunk or complete resection with nerve grafting was recommended.

Conclusion: Erosion into the external auditory canal from facial nerve schwannomas presents a unique management dilemma. In addition to facial nerve function, issues such as conductive hearing loss, canal cholesteatoma, otitis externa, and chronic otitis media must all be considered. Treatment must be tailored to the individual patient. In young patients who face near-certain tumor growth and future complications, early microsurgical resection with nerve grafting is recommended. In older patients who remain minimally symptomatic, observation is reasonable.