Vestibular schwannoma (acoustic neuroma)
Vestibular schwannoma is a benign Schwann-cell tumor of CN VIII in the internal auditory canal/cerebellopontine angle that presents with slowly progressive unilateral sensorineural hearing loss and disequilibrium rather than true vertigo. Diagnosis rests on asymmetric audiometry followed by contrast-enhanced MRI, and management is a size- and growth-driven choice among observation, stereotactic radiosurgery, and microsurgical resection.
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What this article covers
- Overview
Benign Schwann-cell tumor of the vestibular division of the vestibulocochlear nerve (cranial nerve VIII, CN VIII): arises within the internal auditory canal and grows toward the cerebellopontine…
- Epidemiology
Most common cerebellopontine angle tumor: the leading cause of a mass lesion at this location.
- Risk factors
NF2-related schwannomatosis: autosomal dominant mutation of the NF2 tumor-suppressor gene (merlin) on chromosome 22; defines the bilateral, syndromic form and predisposes to earlier onset.
- Pathophysiology
Schwann cell proliferation along CN VIII: the tumor arises from the myelin-forming Schwann cells ensheathing the vestibular nerve, most often within the internal auditory canal.
- Clinical features
Unilateral, progressive sensorineural hearing loss: the classic and most common presenting symptom, typically gradual over months to years.
- Differential diagnosis
Meniere disease: episodic, fluctuating triad of sensorineural hearing loss, tinnitus, and true vertigo, in contrast to the steadily progressive hearing loss and disequilibrium (not episodic vertigo) of vestibular schwannoma.
- Diagnosis
Confirmed by contrast-enhanced MRI showing an enhancing internal auditory canal/cerebellopontine angle mass: there is no formal clinical diagnostic criteria set; the diagnosis is established by…
- Management
Confirm tumor size, growth rate, and symptom burden before choosing a strategy: management is size-, growth-, and symptom-driven rather than a single default treatment, so the first step after…
- Complications
Permanent sensorineural hearing loss: the natural consequence of tumor growth and a possible consequence of treatment, particularly resection.
- Prognosis
Generally favorable given the tumor's benign, slow-growing nature: most tumors grow slowly, and long-term tumor control is achieved with either radiosurgery or resection for tumors that require treatment.
- Prevention
No established primary prevention for sporadic vestibular schwannoma: there is no modifiable risk factor or screening test recommended for the general population given the tumor's low incidence and typically benign course.
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