Acoustic Neuroma

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An Acoustic Neuroma, also known as Vestibular Schwannoma, is a rare and Benign Tumor that grows on the eighth cranial nerve, which runs from the inner ear to the brain. It is one of the most common types of tumors in the nervous system.

Etymology

The term “acoustic” comes from the Greek word “akustikos,” meaning “relating to sound.” The tumor is named for its origin in the eighth cranial nerve, which is responsible for transmitting sound vibrations from the inner ear to the brain. “Neuroma” refers to a mass or tumor that arises from nerve tissue.

Pathology

An Acoustic Neuroma is a Slow-Growing tumor composed of Schwann Cells, a type of glial cell that supports and protects nerves. The tumor grows slowly over time, but can cause symptoms if it compresses the surrounding brain tissue.

The tumor typically consists of:

Causes

The exact causes of Acoustic Neuroma are not fully understood, but several factors may contribute to its development:

Symptoms

Symptoms of an Acoustic Neuroma typically develop gradually and may include:

  • Hearing loss or tinnitus (ringing in the ears)
  • Nausea and vomiting due to increased Intracranial Pressure
  • Balancing problems, such as dizziness or vertigo
  • Difficulty walking or maintaining balance

Diagnosis

Diagnosis of an Acoustic Neuroma usually involves a combination of:

  • Audiological evaluation (hearing tests)
  • Imaging studies:
    • Magnetic Resonance Imaging (MRI)
    • Computed Tomography (CT) scan
  • Laboratory tests: Blood work, imaging-guided biopsies

Treatment

Treatment options for acoustic neuromas vary depending on their size and location. The goal of treatment is to:

  • Relieve symptoms
  • Preserve hearing and balance function
  • Prevent further growth or damage to surrounding tissue

Options include:

  • Surgery: Neurosurgical clipping or removal of the tumor
  • Stereotactic radiosurgery (SRS): High-precision radiation therapy
  • Observation: In some cases, treatment may be delayed until symptoms become severe.

Prognosis

The prognosis for acoustic neuromas is generally good, especially when caught early. However, if left untreated or undertreated, the tumor can:

  • Grow larger and cause increased Intracranial Pressure
  • Press on surrounding brain tissue, leading to permanent damage

In rare cases, an Acoustic Neuroma may be malignant (cancerous), but this is extremely uncommon.

Prevalence

Acoustic neuromas are relatively rare, affecting approximately 1 in 100,000 people worldwide. They are more common among certain populations:

  • Individuals with a Family History of acoustic neuromas
  • People over the Age of 40
  • Those with certain genetic conditions (e.g., MEN2A)

Complications

While rare, complications from an Acoustic Neuroma may include:

  • Hearing loss or tinnitus
  • Nausea and vomiting due to increased Intracranial Pressure
  • Balance problems or vertigo
  • Eye movement abnormalities

It is essential to seek medical attention if symptoms persist or worsen over time.

References

  1. American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS). (2019). Vestibular Schwannoma.
  2. National Institute on Deafness and Other Communication Disorders (NIDCD). (2020). Acoustic Neuroma.
  3. Mayo Clinic. (2020). Vestibular Schwannoma (Acoustic Neuroma).

Additional Resources