Acoustic Neuroma (Vestibular Schwannoma)

More specifically, these tumours develop from Schwann cells, which form a sheath around the vestibular part of the nerve—hence the name “vestibular schwannoma.” They affect approximately 1 in 100,000 people per year.

The tumour begins in the internal auditory canal, where it compresses the cochlear nerve and causes progressive, unilateral sensorineural hearing loss. An audiogram can show the degree of hearing loss. Tinnitus (sounds in the ear) often accompanies the deafness. While the schwannoma originates on the vestibular nerve, vertigo is uncommon because the tumour generally grows very slowly. It eventually grows intracranially, often forming a spherical shape. At this point, it can cause other neurological symptoms as it compresses neighbouring structures. Diagnosis is based on MRIs, as they are the most sensitive and reliable way to detect acoustic neuromas.

The choice of treatment depends on numerous factors and can require the skills of several specialists (ENT doctors, neurosurgeons and radiation oncologists). Québec City’s Hôpital de l’Enfant-Jésus has an otoneurology clinic that brings together each of these specialties, allowing for a multidisciplinary decision-making approach that can be tailored to each patient. Radiological monitoring with annual control MRIs is often recommended for senior patients if the tumour is not likely to cause serious complications.

Otherwise, stereotactic radiation therapy can prevent tumour growth in more than 90% of cases. It is used for small and medium tumours. Different types of radiation can be applied, in one or several sessions. Complications are less common with radiation than with surgery. However, radiation does not eliminate the tumour entirely. For that reason, the patient will need to be monitored and receive regular scans for the rest of their life.

Finally, surgical treatment aims to remove the entirety of the tumour while preserving the surrounding nerves and brain structures. There are many surgical approaches available, each with their own advantages and disadvantages. Surgery is performed with a dual surgical team, relying on the skills of a neurosurgeon and an ENT doctor.