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Understanding Acoustic Neuroma: Symptoms, Causes, and Treatments

Alan Lucks | MD

Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on December 7th, 2023.

Key Takeaways

  • This noncancerous tumor grows on the vestibular nerve (eighth cranial nerve) and affects roughly 1 in 100,000 people annually, with most cases occurring between ages 30-60.

  • Symptoms typically develop gradually over months to years, starting with unilateral hearing loss in 90% of cases, followed by tinnitus (70%) and balance problems (67%).

  • While 95% of cases occur sporadically with unknown cause, the remaining 5% stem from neurofibromatosis type II (NF2), an inherited condition that often produces bilateral tumors.

  • Tumors smaller than 3cm with minimal symptoms are often monitored with annual MRI scans, as growth rates average only 1-2mm per year in most patients.

  • Surgical approaches include retrosigmoid, translabyrinthine, and middle fossa techniques, with hearing preservation possible in 30-70% of cases depending on tumor size and surgical approach used.

An acoustic neuroma, also known as a vestibular schwannoma, is a noncancerous growth that develops on the eighth cranial nerve, which connects the inner ear to the brain. This nerve has two parts: one responsible for transmitting sound and the other for sending balance information from the inner ear to the brain.

Acoustic neuromas typically grow slowly over several years. While they do not invade the brain, larger tumors can press on it and nearby cranial nerves, potentially causing serious complications.

Symptoms of Acoustic Neuroma

Early symptoms of an acoustic neuroma may be subtle and often attributed to normal aging changes. These symptoms include:

  • Gradual hearing loss in one ear

  • Ringing in the ear (tinnitus)

  • Feeling of fullness in the ear

  • Problems with balance

  • Vertigo (feeling like the world is spinning)

  • Facial numbness, tingling, or weakness

  • Taste changes

  • Difficulty swallowing and hoarseness

  • Headaches

  • Clumsiness or unsteadiness

  • Confusion

If you experience any of these symptoms, it's important to consult your doctor for an accurate diagnosis and appropriate treatment.

Causes of Acoustic Neuroma

There are two types of acoustic neuroma:

Sporadic form (95% of cases): The cause is unknown, but exposure to high doses of radiation to the head and neck is a known risk factor.

Neurofibromatosis type II (NF2) associated form (5% of cases): An inherited disorder characterized by the growth of noncancerous tumors in the nervous system, often occurring in both ears by age 30.

Treatment Options for Acoustic Neuroma

The three main treatment options for acoustic neuroma are:

Observation (watchful waiting)

Periodic monitoring with MRI scans, suitable for slow-growing tumors causing no serious symptoms.

Surgery

Removal of all or part of the tumor using one of three approaches:

  • Translabyrinthine (for tumors larger than 3 cm)

  • Retrosigmoid/sub-occipital (for tumors of any size, with the possibility of preserving hearing)

  • Middle fossa (for small tumors confined to the internal auditory canal, with the possibility of preserving hearing)

Radiation therapy

Delivered using state-of-the-art techniques to target the tumor while minimizing damage to surrounding tissue. Options include:

  • Single fraction stereotactic radiosurgery (SRS)

  • Multi-session fractionated stereotactic radiotherapy (FRS)

Understanding Acoustic Neuroma: Symptoms, Causes, and Treatments

The choice of treatment depends on factors such as tumor size, growth rate, patient age, overall health, symptom severity, impact on quality of life, and whether the acoustic neuroma is associated with NF2 or is the sporadic form. NF2-associated tumors often require different treatment considerations due to the likelihood of bilateral tumors and the inherited nature of the condition. Your doctor will discuss the best options for your specific situation.

For more information on acoustic neuroma, visit:

The Bottom Line

Most acoustic neuromas grow slowly and can be safely monitored, but early detection is crucial since smaller tumors offer better treatment outcomes and hearing preservation chances. Treatment decisions depend on tumor size, growth rate, patient age, and hearing status rather than following a one-size-fits-all approach. If you're experiencing one-sided hearing loss or persistent balance issues, Doctronic can help connect you with specialists for proper evaluation.

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