Vestibular schwannoma

Vestibular schwannoma, also known as acoustic neuroma or acoustic neurinoma, is a benign (non-cancerous) tumor that arises from the Schwann cells of the vestibulocochlear nerve (cranial nerve VIII), which connects the inner ear to the brain. This tumor typically develops in the internal auditory canal and can extend into the cerebellopontine angle. Although histologically benign, vestibular schwannomas can cause significant morbidity due to compression of surrounding neural structures. The vast majority of cases are unilateral and sporadic, while bilateral vestibular schwannomas are the hallmark of neurofibromatosis type 2 (NF2), a genetic condition caused by mutations in the NF2 (merlin) gene on chromosome 22. The most common presenting symptoms include progressive unilateral sensorineural hearing loss, tinnitus (ringing in the ear), and balance disturbances or vertigo. As the tumor enlarges, it may compress the trigeminal nerve causing facial numbness, or the facial nerve causing facial weakness. In rare cases of very large tumors, brainstem compression can lead to headaches, hydrocephalus, and potentially life-threatening complications. Diagnosis is typically confirmed through gadolinium-enhanced magnetic resonance imaging (MRI) of the brain and audiometric testing. Treatment options depend on tumor size, growth rate, patient age, hearing status, and overall health. The three main management strategies include observation with serial imaging (watch-and-wait approach) for small or slow-growing tumors, microsurgical resection, and stereotactic radiosurgery (such as Gamma Knife). For sporadic cases, the prognosis is generally favorable, though hearing preservation remains a significant challenge regardless of the treatment approach chosen. Research into targeted molecular therapies, particularly for NF2-associated tumors, is ongoing.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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