An acoustic neuroma, also known as a vestibular schwannoma, is a benign tumor that develops on the vestibulocochlear nerve. This nerve is responsible for hearing and balance and runs from the inner ear to the brain. As the tumor grows, it can press against nearby structures, including the hearing and balance nerves, and in more advanced cases, the brainstem. Although acoustic neuromas are typically slow-growing, early evaluation is critical to prevent long-term complications.
Causes of Acoustic Neuroma
Most acoustic neuromas occur spontaneously, but certain factors may increase the risk:
- Genetic Conditions: Neurofibromatosis type II (NF2), a rare inherited disorder, is associated with bilateral acoustic neuromas.
- Spontaneous Mutation: In the majority of cases, a random mutation in the gene responsible for controlling Schwann cell growth is thought to be the cause.
- Radiation Exposure: Rarely, exposure to high doses of radiation to the head or neck may contribute to tumor development.
Symptoms of Acoustic Neuroma
Symptoms often develop gradually as the tumor enlarges and compresses surrounding structures:
- Progressive hearing loss in one ear (unilateral sensorineural hearing loss)
- Tinnitus (ringing in the affected ear)
- Unsteadiness or balance problems
- Dizziness or vertigo
- A feeling of fullness in the ear
- Facial numbness or weakness (as the tumor impacts the facial or trigeminal nerves)
- In rare, advanced cases, headaches or hydrocephalus due to brainstem compression
Diagnosis
Accurate diagnosis involves a combination of hearing assessments and imaging studies:
- Audiogram: A hearing test to evaluate the extent and pattern of hearing loss.
- MRI with Contrast: The gold standard imaging method to visualize the size, location, and characteristics of the tumor.
Treatment Options
Treatment depends on the tumor’s size, location, patient age, overall health, and hearing status:
- Observation (Watchful Waiting): For small tumors with few or manageable symptoms, regular MRI scans may be used to monitor growth over time. Many tumors grow slowly, if at all, and can be safely watched for many years.
- Microsurgical Removal: Surgical options include various approaches such as retrosigmoid, translabyrinthine, or middle fossa, chosen based on tumor size and location, patient age, and hearing preservation goals.
- Stereotactic Radiosurgery: A non-invasive option (e.g., Gamma Knife) that delivers focused radiation to halt tumor growth, often used in small growing tumors, or in patients who can’t have or don’t want surgery.
When to See a Specialist
If you are experiencing asymmetric hearing loss, persistent tinnitus, or unexplained balance issues, it is important to seek evaluation by an otolaryngologist or neurotologist. Early diagnosis allows for a broader range of treatment options and a better chance of preserving hearing and neurologic function.