Acoustic Neuroma

Definition

An acoustic neuroma, also known as a vestibular schwannoma, is a non-cancerous tumor that develops on the main nerve from the ear to the brain (the vestibulocochlear nerve). This nerve is responsible for hearing and balance, and the growth of the tumor can impact these functions.

5 Must Know Facts For Your Next Test

1. Acoustic neuromas are the most common type of tumor that develops in the cerebellopontine angle, the space between the brain and the inner ear.
2. These tumors typically grow slowly, often taking years to produce noticeable symptoms, which can include hearing loss, tinnitus (ringing in the ear), vertigo, and balance problems.
3. Acoustic neuromas are usually benign, meaning they are non-cancerous and do not spread to other parts of the body, but they can still cause significant health problems due to their location and growth.
4. Diagnosis of an acoustic neuroma typically involves a combination of imaging tests, such as MRI or CT scans, and hearing tests, such as an audiogram.
5. Treatment options for acoustic neuromas can include observation (watchful waiting), surgery to remove the tumor, or radiation therapy to shrink or stop the growth of the tumor.

Review Questions

• Explain the role of the vestibulocochlear nerve (cranial nerve VIII) in the development of an acoustic neuroma.
  • The vestibulocochlear nerve, also known as the auditory or acoustic nerve, is responsible for transmitting hearing and balance information from the inner ear to the brain. Acoustic neuromas develop on this nerve, typically in the cerebellopontine angle, the space between the brain and the inner ear. As the tumor grows, it can compress and damage the vestibulocochlear nerve, leading to the common symptoms of hearing loss, tinnitus, vertigo, and balance problems. The location and growth of the tumor directly impacts the function of this important cranial nerve, making it a key factor in the development and presentation of an acoustic neuroma.
• Describe the diagnostic process for identifying an acoustic neuroma, including the role of imaging and hearing tests.
  • Diagnosing an acoustic neuroma typically involves a combination of imaging tests and hearing assessments. Magnetic resonance imaging (MRI) or computed tomography (CT) scans are commonly used to visualize the tumor and its location within the cerebellopontine angle. These imaging tests can provide detailed information about the size, shape, and characteristics of the acoustic neuroma. Additionally, hearing tests, such as an audiogram, are essential for evaluating the patient's hearing function and identifying any hearing loss or other auditory symptoms associated with the tumor. The results of these diagnostic tests, when considered together, allow healthcare providers to confirm the presence of an acoustic neuroma and develop an appropriate treatment plan.
• Evaluate the potential treatment options for an acoustic neuroma, considering the benefits, risks, and factors that may influence the choice of treatment approach.
  • The treatment of an acoustic neuroma depends on various factors, including the size and growth rate of the tumor, the patient's age and overall health, and the severity of the symptoms. The main treatment options include observation (watchful waiting), surgical removal of the tumor, and radiation therapy. Observation may be recommended for small, slow-growing tumors that are not causing significant symptoms. Surgery, either through a traditional open approach or a minimally invasive technique, can be effective in removing the tumor and relieving pressure on the vestibulocochlear nerve, but carries risks such as hearing loss, facial paralysis, and cerebrospinal fluid leaks. Radiation therapy, including stereotactic radiosurgery, can be used to shrink or stop the growth of the tumor, often preserving hearing and other neurological functions. The choice of treatment ultimately depends on a careful evaluation of the individual patient's needs, risks, and preferences, in collaboration with their healthcare team.

Related terms

Vestibular System:

The vestibular system is the sensory system that provides the leading contribution to the sense of balance and spatial orientation. It is located in the inner ear and includes the semicircular canals and the otolith organs.

Cranial Nerves:

Cranial nerves are the nerves that emerge directly from the brain, in contrast to the spinal nerves, which emerge from the spinal cord. There are 12 pairs of cranial nerves, and the vestibulocochlear nerve (VIII) is responsible for hearing and balance.

Schwann Cells:

Schwann cells are the principal glial cells of the peripheral nervous system. They produce the myelin sheath that insulates many peripheral nerve axons, which is essential for the efficient transmission of electrical signals.