schwannomatosis

Schwannomatosis: A Rare Neurological Disorder

Schwannomatosis is a rare genetic disorder characterized by the growth of multiple noncancerous (benign) tumors called schwannomas on nerve tissue. These tumors can develop on nerves in various parts of the body, including the ears, brain, spine, eyes, and peripheral nerves.

Key Features:

• Multiple benign tumors (schwannomas) grow on nerve tissue
• Tumors can occur on nerves in the ears, brain, spine, eyes, and peripheral nerves
• Rare genetic disorder with an unknown exact frequency of cases
• Can be diagnosed in early adulthood

Types of Schwannomatosis:

While there are different types of schwannomatosis, they all share a common characteristic of multiple schwannomas without concomitant involvement of the vestibular apparatus. The condition can manifest differently based on the size, location, and number of schwannomas.

• NF2-related schwannomatosis (NF2) is characterized by bilateral vestibular schwannomas with associated symptoms such as tinnitus, hearing loss, and balance problems.
• Other types of schwannomatosis may present with different symptoms, including pain, numbness, and neurological complications.

Diagnosis:

A confirmed diagnosis of schwannomatosis can be made if a person meets specific criteria, which include the presence of multiple schwannomas without bilateral vestibular schwannomas. Only a doctor with expertise in schwannomatosis can provide an accurate diagnosis.

References:

• [1] Schwannomatosis is described as a rare syndrome characterized by multiple schwannomas without concomitant involvement of the vestibular apparatus (Source: #4)
• [2] The condition is also referred to as a third major form of neurofibromatosis, which shares a predisposition to multiple nerve sheath tumors (Source: #13)

Common Signs and Symptoms of Schwannomatosis

Schwannomatosis is a rare genetic disorder characterized by the growth of noncancerous (benign) tumors called schwannomas on the nerves that transmit balance and sound impulses from the inner ear to the brain. The signs and symptoms of schwannomatosis can vary widely, but here are some common ones:

• Chronic Pain: Long-lasting pain is a common symptom of schwannomatosis, which can affect any part of the body [2]. In some cases, the pain may be felt in areas where there are no known tumors.
• Numbness and Tingling: Numbness or tingling sensations in the fingers and toes are also common symptoms [4].
• Weakness: Weakness in the muscles is another symptom that can occur due to the compression of nerves by schwannomas [9].
• Balance and Hearing Problems: Schwannomatosis can cause problems with balance and hearing, as the tumors can affect the vestibulocochlear nerve that controls these functions [12].
• Painful Tumors: The growth of painful tumors under the skin is a symptom of schwannomatosis, which can be accompanied by numbness or tingling sensations [7].

Other Possible Symptoms

In addition to the above symptoms, schwannomatosis can also cause:

• Facial Weakness
• Headaches
• Lumps or Swollen Areas under the Skin
• Vision Changes
• Difficulty with Urinating or Bowel Dysfunction

It's essential to note that the degree of pain and tumors vary widely among individuals with schwannomatosis, and some symptoms may be shared with other conditions [5]. A healthcare provider will use a list of diagnostic criteria (a checklist of signs and symptoms) to determine whether or not a patient may be given a diagnosis of schwannomatosis.

References

[1] Context result 4 [2] Context result 2 [3] Context result 6 [4] Context result 4 [5] Context result 5 [6] Context result 7 [7] Context result 11 [8] Context result 12 [9] Context result 13

Diagnosing Schwannomatosis: A Comprehensive Overview

Schwannomatosis, a rare genetic disorder, requires a thorough diagnostic process to confirm its presence. The diagnostic criteria for schwannomatosis have been updated over the years, and a healthcare professional with expertise in this area is essential for an accurate diagnosis.

Diagnostic Criteria

To diagnose schwannomatosis, a patient must meet one of the following conditions:

• Presence of two or more lesions on appropriate imaging consistent with non-intradermal schwannomas (criterion 11)
• Genetic testing has been incorporated into the updated diagnostic criteria for schwannomatosis published in 2022 (criterion 12)

Diagnostic Tests

The diagnosis of schwannomatosis involves several forms of testing, including:

• Imaging tests: MR (magnetic resonance) and CT (computed tomography) scans may be performed to look for tumors (criterion 4)
• Genetic testing: Testing is available for the SMARCB1 gene mutation associated with some cases of schwannomatosis (criteria 6 and 8)
• Physical exam: A healthcare provider will perform a physical exam to learn more about your symptoms and family medical history (criterion 10)

Additional Tests

Other tests may be performed to diagnose NF2-related schwannomatosis or SMARCB1- and LZTR1-related schwannomatosis, including:

• Eye exam
• MR and CT scans to look for tumors

Importance of Genetic Testing

Genetic testing is essential in establishing a diagnosis of schwannomatosis. It has been incorporated into the updated diagnostic criteria for schwannomatosis published in 2022 (criterion 12). This testing can help confirm a diagnosis, leading to better management and treatment options.

References:

• Criterion 11: A healthcare provider will diagnose schwannomatosis-NOS (not otherwise specified) can be made if both of the following criteria are met and genetic testing was not performed or is not available: • presence of two or more lesions on appropriate imaging consistent with non-intradermal schwannomas, and
• Criterion 12: Genetic testing has been incorporated into the updated diagnostic criteria for schwannomatosis published in 2022, whereas it was not included in the previous diagnostic criteria.
• Criterion 4: The diagnosis of schwannomatosis includes several forms of testing. MR (magnetic resonance) and CT (computed tomography) scans may be performed to look for ...
• Criterion 6: Genetic testing for SMARCB1 can help confirm a diagnosis of schwannomatosis, which can lead to better management.
• Criterion 8: Genetic testing is available for the SMARCB1 gene mutation, which is associated with some cases of schwannomatosis. Testing is also offered for another recently ...
• Criterion 10: A healthcare provider will diagnose schwannomatosis after a physical exam and testing. During the exam, your provider will learn more about your symptoms and your family medical history.
• Criterion 11: A diagnosis of schwannomatosis-NOS (not otherwise specified) can be made if both of the following criteria are met and genetic testing was not performed or is not available: • presence of two or more lesions on appropriate imaging consistent with non-intradermal schwannomas, and
• Criterion 12: Genetic testing has been incorporated into the updated diagnostic criteria for schwannomatosis published in 2022, whereas it was not included in the previous diagnostic criteria.

Treatment Options for Schwannomatosis

Schwannomatosis, a rare genetic disorder, can be managed through various treatment options to alleviate symptoms and improve quality of life.

• Medications: While there is no cure for schwannomatosis, medications can help manage chronic pain, neurologic problems, hearing loss, and other symptoms. Commonly prescribed drugs include:
  • Gabapentin [9] (a neuropathic agent) to control nerve pain
  • Duloxetine (Cymbalta) [15] to alleviate chronic pain
• Brigatinib: A recent study has shown promising results in using brigatinib, a medication already used for lung cancer, as a potential treatment for NF2-related schwannomatosis. Brigatinib may shrink tumors associated with neurofibromatosis type 2 (NF2)-related schwannomatosis [4]. Additionally, brigatinib treatment resulted in radiographic responses in multiple tumor types and clinical benefit in a heavily pretreated cohort of patients with NF2-SWN [5].
• Scrambler Therapy: This relatively new neuromodulatory treatment approach can quickly, safely, and inexpensively relieve neuropathic pain in schwannomatosis patients [15].

Important Considerations

Early diagnosis and treatment are crucial for a good outcome. If tumors become cancerous, standard cancer therapies such as surgery, chemotherapy, and radiation therapy may be necessary.

It is essential to consult with a healthcare professional to determine the best course of treatment for individual cases of schwannomatosis.

References:

[4] Jun 21, 2024 - Researchers have evidence that brigatinib may shrink tumors associated with neurofibromatosis type 2 (NF2)-related schwannomatosis. [5] by SR Plotkin · 2024 · Cited by 6 — Brigatinib treatment resulted in radiographic responses in multiple tumor types and clinical benefit in a heavily pretreated cohort of patients with NF2-SWN. [9] by T Murphy · 2022 · Cited by 3 — Classical conservative management of chronic neuropathic pain associated with schwannomatosis involves neuropathic agents including gabapentin, ... [15] Schwannomatosis patients (SP) suffer from chronic nerve pain that is often inadequately relieved. Scrambler therapy (ST) can relieve neuropathic pain quickly, safely, and inexpensively.

The differential diagnosis for schwannomatosis primarily involves distinguishing it from neurofibromatosis type 2 (NF2). This can be particularly challenging in cases where the segmental or mosaic form of NF2 is present, as vestibular schwannomas may not develop in such patients. Genetic studies are often required to differentiate between these two conditions.

• Key differences:
  • Schwannomatosis is characterized by multiple schwannomas without vestibular tumors.
  • Neurofibromatosis type 2 (NF2) involves the development of both vestibular and non-vestibular schwannomas.
• Genetic studies: Molecular diagnosis may improve differential diagnosis. For instance, a germline SMARCB1 pathogenic variant was identified in a family affected by schwannomatosis in 2007.

References:

• [3] Differential Diagnosis
• [13] Molecular diagnosis may improve the differential diagnosis.
• [7] When multiple schwannomas are observed, the main differential diagnosis is neurofibromatosis type 2, although there is phenotypic overlap and genetic studies may be required to distinguish between these two possibilities.