Acoustic neurinoma

Acoustic Neurinoma Acoustic neurinoma, also known as vestibular schwannoma, is a rare, benign tumor that develops on the eighth cranial nerve, which is responsible for hearing and balance. This article provides a comprehensive overview of acoustic neurinoma, including its causes, symptoms, diagnosis, treatment, and prognosis.

Causes

Acoustic neurinomas are typically caused by the overproduction of Schwann cells, which are responsible for the myelin sheath that insulates nerve fibers. The exact cause of this overproduction is not well understood, but genetic factors, particularly mutations in the NF2 gene, are known to play a significant role.

Genetic Factors

The NF2 gene provides instructions for making a protein called merlin, which acts as a tumor suppressor. Mutations in this gene can lead to uncontrolled cell growth, resulting in the formation of tumors such as acoustic neurinomas. Individuals with neurofibromatosis type II (NF2) are at a higher risk of developing these tumors.

Symptoms

The symptoms of acoustic neurinoma can vary depending on the size and location of the tumor. Common symptoms include:

• Hearing loss, usually gradual and affecting one ear
• Tinnitus, or ringing in the affected ear
• Balance problems or dizziness
• Facial numbness or weakness

In some cases, larger tumors can press on nearby cranial nerves or brain structures, leading to more severe symptoms.

Diagnosis

Diagnosis of acoustic neurinoma typically involves a combination of hearing tests, imaging studies, and neurological examinations.

Hearing Tests

Audiometry is used to assess the degree of hearing loss and to help differentiate between conductive and sensorineural hearing loss.

Imaging Studies

Magnetic resonance imaging (MRI) is the preferred method for visualizing acoustic neurinomas. It provides detailed images of the brain and can detect even small tumors.

Treatment

Treatment options for acoustic neurinoma depend on the size and growth rate of the tumor, as well as the patient's overall health and preferences.

Observation

For small, slow-growing tumors, a "watch and wait" approach may be recommended, with regular monitoring through MRI scans.

Surgery

Surgical removal of the tumor is a common treatment, especially for larger or symptomatic tumors. The goal is to remove the tumor while preserving hearing and facial nerve function.

Radiation Therapy

Stereotactic radiosurgery, such as Gamma Knife, is a non-invasive option that uses focused radiation to stop tumor growth. It is often used for smaller tumors or in patients who are not surgical candidates.

Prognosis

The prognosis for patients with acoustic neurinoma is generally good, especially when the tumor is detected early and treated appropriately. However, some patients may experience long-term effects such as hearing loss or facial nerve dysfunction.

See Also

• Neurofibromatosis type II
• Cranial nerves
• Hearing loss

External Links

• [Acoustic Neurinoma Information - National Institute on Deafness and Other Communication Disorders](https://www.nidcd.nih.gov/)
• [Vestibular Schwannoma - American Hearing Research Foundation](https://www.american-hearing.org/)

NIH genetic and rare disease info

• NIH info on Acoustic neurinoma

Acoustic neurinoma is a rare disease.