vestibular schwannomatosis

Vestibular Schwannomatosis: A Rare Genetic Disorder

Vestibular schwannomatosis, also known as neurofibromatosis type II (NF2), is a rare genetic disorder characterized by the development of multiple noncancerous (benign) tumors called schwannomas on nerves throughout the body. These tumors can grow on nerves in the ears, brain, spine, and eyes.

Key Features:

• Multiple Tumors: Vestibular schwannomatosis is marked by the presence of multiple schwannomas, which are typically benign but can cause significant symptoms.
• Genetic Basis: The condition is inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to increase the risk of developing the disorder.
• Age of Onset: Symptoms usually appear in people over age 30, although some cases have been reported in younger individuals.

Symptoms:

• Tinnitus: Ringing or buzzing sounds in the ears
• Hearing Loss: Gradual loss of hearing in one ear (unilateral)
• Balance Dysfunction: Difficulty with balance and coordination

Other Characteristics:

• Schwannomas on Other Nerves: In addition to vestibular schwannomas, people with this condition may develop schwannomas on other nerves, including those in the brain, spine, and eyes.
• Bilateral Vestibular Schwannomas: A hallmark of NF2-related vestibular schwannomatosis is the presence of bilateral vestibular schwannomas (tumors in both ears).

Incidence:

• Rare Disorder: Vestibular schwannomatosis affects about one in 40,000 people.
• Higher Incidence in Whites: The condition is more common among White individuals than non-Whites.

References:

• [1] Schwannomatosis is a disorder characterized by multiple nonvestibular, nonintradermal schwannomas. (Source: #13)
• [2] Vestibular schwannomas are the third most common intracranial nonmalignant tumor entity after meningiomas and pituitary adenomas. (Source: #15)

Common Signs and Symptoms of Vestibular Schwannomatosis

Vestibular schwannomatosis, also known as schwannomatosis, is a rare genetic disorder characterized by the growth of multiple non-cancerous tumors (schwannomas) along the nerves. The symptoms of vestibular schwannomatosis can vary depending on the location and size of the tumors, but here are some common signs and symptoms:

• Headaches: Headaches are one of the most common symptoms of vestibular schwannomatosis, affecting up to 90% of patients [1].
• Hearing Loss: Hearing loss is a common symptom, particularly on the side of the acoustic neuroma. In fact, hearing loss is the most common presenting symptom in 90% of patients [5].
• Balance and Gait Issues: Patients with vestibular schwannomatosis may experience balance and gait issues, dizziness, and problems with coordination [4].
• Facial Weakness: Facial weakness or numbness can occur due to pressure on the facial nerve [8].
• Chronic Pain: Chronic pain is a common symptom reported by patients with vestibular schwannomatosis, affecting up to 68% of patients [7].
• Tinnitus and Ringing in the Ear: Some patients may experience tinnitus (ringing in the ear) or other auditory symptoms due to pressure on the nerves [6].

Other Possible Symptoms

In addition to these common symptoms, vestibular schwannomatosis can also cause:

• Difficulty urinating or bowel dysfunction
• Lumps or swollen areas where tumors form under the skin
• Numbness, weakness, tingling, and headaches depending on the location of the tumors and which nerves are affected

It's essential to note that not everyone with vestibular schwannomatosis will experience all of these symptoms. The severity and frequency of symptoms can vary significantly from person to person.

References:

[1] Jul 19, 2024 — The tumors caused by schwannomatosis usually are not cancerous. Symptoms can include headaches, hearing loss, trouble with balance and pain. [2] Symptoms of Schwannomatosis · Difficulty urinating or bowel dysfunction · Facial weakness · Headaches · Lumps or swollen areas where tumors form under the skin ... [3] Jan 1, 2017 — Schwannomatosis symptoms can include numbness, weakness, tingling, and headaches, depending on the location of the tumors and which nerves are ... [4] Schwannomatosis symptoms can include balance and gait issues, dizziness, headache, facial weakness, numbness, tinnitus, and progressive hearing loss. [5] The most common symptom of acoustic neuromas, occurring in 90% of patients, is hearing loss on the side of the acoustic neuroma. Acoustic neuroma is diagnosed ... [6] Jun 20, 2023 — Pressure from an acoustic neuroma can cause hearing loss, ringing in the ear and problems with balance. Another name for an acoustic neuroma is ... [7] by VL Merker · 2012 · Cited by 221 — The most common symptom reported by schwannomatosis patients was chronic pain (68%, 59 of 87 patients), which included both local and multifocal or diffuse pain ... [8] Although the most common sign of schwannomatosis is pain, the tumors in schwannomatosis may occasionally press on nerves, causing numbness or tingling, muscle ...

Diagnostic Tests for Vestibular Schwannomatosis

Vestibular schwannomatosis, also known as acoustic neuroma or schwannoma, is a rare genetic disorder characterized by the growth of non-cancerous tumors on the nerves responsible for balance and hearing. The diagnostic tests for vestibular schwannomatosis are crucial in identifying the condition and determining its severity.

Imaging Tests

• Magnetic Resonance Imaging (MRI): MRI scans with contrast dye are usually used to diagnose an acoustic neuroma. This imaging test can detect tumors as small as 1-2 mm in size, making it a critical tool in early detection [4].
• High-resolution brain MRI: Doctors may perform a high-resolution brain MRI that also looks at the internal auditory canal, which contains the eight cranial nerves. This test helps identify the location and size of the tumor [3].

Genetic Testing

• NF2 genetic testing: Genetic tests can help identify individuals with NF2-related schwannomatosis, a condition characterized by bilateral vestibular schwannomas [11].
• LZTR1 and SMARCB1 genetic testing: Genetic tests may also be used to diagnose LZTR1- and SMARCB1-related schwannomatosis, which are distinct from NF2-related schwannomatosis [10].

Other Diagnostic Tests

• Hearing test (audiogram): A hearing test is essential in diagnosing vestibular schwannomatosis, as it can detect unilateral sensorineural hearing loss [15].
• Electronystagmography and auditory brainstem responses: These tests help evaluate the balance and hearing functions of the affected individual [3].

Monitoring the Condition

Imaging tests are also used to monitor the condition after diagnosis. Genetic tests may be repeated periodically to assess the progression of the disease.

References:

[3] Context 3, 11 [4] Context 4 [10] Context 10 [11] Context 11 [15] Context 15

Treatment Options for Vestibular Schwannomatosis

Vestibular schwannomatosis, also known as NF2-related Schwannomatosis, is a rare genetic disorder characterized by the growth of non-cancerous tumors in the nervous system. While surgery and radiation therapy are common treatment options, researchers have been exploring various drug treatments to manage this condition.

Bevacizumab: A Promising Treatment Option

Recent studies have shown that Bevacizumab, a medication already used for lung cancer, may be effective in treating vestibular schwannomatosis. This targeted therapy works by inhibiting the growth of new blood vessels that feed the tumors, thereby slowing their growth.

• According to study [7], Bevacizumab demonstrated positive effects on hearing, tumor control, and symptoms in NF2-related schwannomatosis, albeit with common adverse events.
• Another study [9] found that Bevacizumab is currently favored in treating VSs due to its superior outcomes compared to other targeted therapies like Brigatinib.

Brigatinib: A Potential Tumor-Suppressing Agent

Research has also shown that Brigatinib, a compound already used for lung cancer, may have tumor-suppressing properties in cell and animal models of NF2-related diseases. This suggests that Brigatinib could be a potential treatment option for vestibular schwannomatosis.

• Studies [5] and [6] have demonstrated the effectiveness of Brigatinib in suppressing tumor growth in cell and animal models.
• Another study [8] found that Brigatinib has tumour-suppressing properties in cell and animal models of NF2-related diseases.

Other Treatment Options

While Bevacizumab and Brigatinib show promise, other treatment options are also being explored. These include:

• Anti-angiogenic therapy: This approach targets the growth of new blood vessels that feed the tumors.
• Histone deacetylase inhibitors: These medications have been shown to inhibit tumor growth in preclinical models.

Conclusion

While surgery and radiation therapy remain common treatment options for vestibular schwannomatosis, researchers are actively exploring various drug treatments to manage this condition. Bevacizumab and Brigatinib show promise as potential treatment options, but further research is needed to confirm their effectiveness and safety.

Differential Diagnosis of Vestibular Schwannomatosis

Vestibular schwannomatosis, also known as neurofibromatosis type 2 (NF2), is a rare genetic disorder characterized by the growth of noncancerous tumors called schwannomas on the nerves that transmit balance and sound impulses from the inner ear. The differential diagnosis of vestibular schwannomatosis involves distinguishing it from other conditions that may present with similar symptoms.

Conditions to Consider:

• NF2-related Schwannomatosis: This is a type of neurofibromatosis characterized by bilateral vestibular schwannomas, tinnitus, hearing loss, and balance dysfunction. The average age of onset is 18-24 years.
• Schwannomatosis without identified mutation in blood: This condition can be diagnosed when an individual does not meet criteria for NF2-related schwannomatosis, SMARCB1-related schwannomatosis, or LZTR1-related schwannomatosis, and has bilateral vestibular schwannomas < 70 years of age.
• Unilateral Vestibular Schwannoma: This is a rare condition characterized by the growth of a single schwannoma on one side of the inner ear. It can be associated with NF2 or schwannomatosis.

Key Features to Consider:

• Bilaterality: The presence of bilateral vestibular schwannomas is a key feature that distinguishes NF2-related schwannomatosis from other conditions.
• Age of onset: The average age of onset for NF2-related schwannomatosis is 18-24 years, while unilateral vestibular schwannoma typically presents in older adults.
• Family history: A family history of NF2 or schwannomatosis can increase the likelihood of a diagnosis.

Diagnostic Criteria:

• NF2-related Schwannomatosis: Bilateral vestibular schwannomas < 70 years of age, tinnitus, hearing loss, and balance dysfunction.
• Schwannomatosis without identified mutation in blood: Bilateral vestibular schwannomas < 70 years of age, unilateral vestibular schwannoma < 70 years with a first-degree relative with NF2, or any two of the following: meningioma, schwannoma (non-vestibular), ependymoma, cerebral calcification, cataract.

Conclusion

The differential diagnosis of vestibular schwannomatosis involves considering several conditions that may present with similar symptoms. A thorough evaluation of clinical features, family history, and diagnostic criteria is essential to arrive at an accurate diagnosis.