Schwannoma: What the Patient Needs to Know

Schwannoma is a type of benign tumor that originates from Schwann cells—essential components of the peripheral nervous system. While typically slow-growing and non-cancerous, these tumors can arise anywhere along peripheral nerves, causing symptoms such as pain, numbness, or weakness depending on their location and size.

Understanding schwannomas, their symptoms, diagnosis, and available treatment options is vital for individuals facing this diagnosis. In this article, we aim to provide a comprehensive guide to help patients navigate their journey with schwannoma.

A schwannoma is a type of benign (non-cancerous) and slow growing tumor that arises from Schwann cells. This cell type provides support and insulation to nerve fibers in the peripheral nervous system. Parts of a Schwann cell wrap around the axons of neurons, forming a myelin sheath.

This helps to facilitate fast transmission of nerve impulses, allowing signals to travel to and from the brain in almost no time at all. Schwannomas are usually not cancerous, which means they do not spread to other parts of the body. Their benign nature and tendency to remain in one place allows treatments such as surgical removal to be potentially curative.

Although they can grow on any peripheral nerve, they are often found on the nerves that control balance and hearing in the inner ear. These are called vestibular schwannomas or acoustic neuromas. Other locations where they may be found include the trigeminal nerve in the brain and nerve roots in the spine.

Most schwannomas cause no symptoms at all. However, if they become large, they can cause different symptoms depending on their location and what nerve is affected.

Symptoms of vestibular schwannomas can include hearing loss or reduction, weakness of the facial muscles, headaches, or even facial numbness. More information on vestibular schwannomas can be found here.

In contrast, spinal nerve root schwannomas may cause a variety of symptoms depending on the extent of compression or irritation of nearby nerves and spinal cord tissue. Common symptoms may include:

• Pain: Persistent or radiating pain along the path of the affected nerve root is a common symptom of spinal nerve root schwannomas. The pain may be localized to the back or neck, or it may radiate along the distribution of the affected nerve, such as into the arms or legs.

• Weakness: Muscle weakness or difficulty moving the limbs may occur if the tumor compresses or impairs the function of the nerve root. Weakness may affect specific muscles or muscle groups innervated by the affected nerve.

• Numbness or Tingling: Sensory changes such as numbness, tingling, or a "pins-and-needles" sensation may occur in the areas supplied by the affected nerve root. These sensory disturbances may affect the arms, legs, or other parts of the body depending on the location of the tumor.

• Muscle Atrophy: Chronic compression or irritation of the nerve root by the tumor may lead to muscle wasting or atrophy over time. Muscle atrophy may result in decreased muscle bulk, strength, and coordination in the affected limbs.

• Changes in Reflexes: Spinal nerve root schwannomas can affect reflexes controlled by the affected nerve roots. Changes in reflexes, such as increased or decreased reflex responses, may be observed during physical examination.

• Bowel or Bladder Dysfunction: In some cases, spinal nerve root schwannomas located in the lower spine may compress the nerves responsible for bowel or bladder function, leading to urinary or fecal incontinence, difficulty urinating, or other bladder or bowel disturbances.


It's important to note that the symptoms of spinal nerve root schwannomas can vary widely from person to person, and not all individuals may experience the same symptoms. Additionally, some schwannomas may be asymptomatic and discovered incidentally on imaging studies performed for other reasons.

If you experience persistent or worsening symptoms suggestive of a schwannoma, it's essential to seek evaluation and diagnosis by a healthcare provider, typically a neurologist or neurosurgeon, who can perform a thorough examination and order appropriate imaging studies to confirm the diagnosis and develop a treatment plan.

The exact cause of schwannoma development is not completely understood, but they are thought to arise due to genetic mutations in Schwann cells. They can occur sporadically, meaning they develop without a known cause, or they may occur as part of a genetic syndrome.

Certain genetic syndromes, such as neurofibromatosis type 2 (NF2) are associated with an increased risk of developing schwannomas. Individuals with NF2 can develop multiple schwannomas and other nervous system tumors during their lifetime.

Exposure to high levels of ionizing radiation may also increase the risk of developing schwannomas. Currently, there are no other well-established environmental or lifestyle risk factors associated with schwannomas.

Schwannomas are relatively uncommon tumors. However, their exact prevalence is not well documented as they may not cause symptoms and are often diagnosed incidentally on imaging studies performed for other reasons.

Some studies estimate that schwannomas account for 8% to 10% of primary brain tumors. Older adults are more commonly affected by schwannomas. However, schwannomas can also develop in children and adolescents. Vestibular schwannoma is the most common type of schwannoma.

A schwannoma is diagnosed with a combination of history taking, physical and neurological exam, imaging tests, and other special tests depending on the nerve affected. The following are tests that may be utilized during the diagnostic workup.

• Imaging Studies: These are the most important tools for diagnosing a schwannoma.
  • Magnetic Resonance Imaging (MRI): An MRI scan is often the best way to see a schwannoma. It can show the size and location of the tumor and how it affects nearby structures. MRI scans with contrast can help distinguish schwannomas from other types of tumors.

  • Computed Tomography (CT) Scan: A CT scan can be helpful, especially if MRI is not available or if the patient has a condition that makes MRI unsafe. It's good for showing the effects of the tumor on bones, such as the spine or skull. It will also be helpful to plan surgery. 
• Biopsy: A small piece of the tumor is removed and looked at under a microscope to make sure it's a schwannoma. This can be done in the same operation as the surgery. 
• Genetic Testing: If there's a reason to think the schwannoma might be part of a genetic condition like Neurofibromatosis Type 2 or Schwannomatosis, genetic testing might be done.

• Special Tests: For a vestibular schwannoma, hearing tests may be performed to guide the management plan and for later comparison after treatment.

The main treatment options for a schwannoma are surgery and, in some cases, radiation therapy. Alternatively, a "watch-and-wait" approach can be taken to observe the schwannoma that is small and asymptomatic.

Surgery is the primary treatment method, and the only potentially curative option, for symptomatic schwannomas. With total surgical removal, recurrence is extremely rare. Most patients report improvement in their symptoms after surgery.

The exact surgical approach will depend on the location of the schwannoma. For vestibular schwannomas, this will require an incision in the scalp. For spinal schwannomas, this will involve an incision in the back and spine.

In some cases, radiation therapy may be performed after surgery for a residual tumor, or as primary treatment when surgery is not an option. This involves the delivery of high-energy radiation beams to the tumor site to prevent its growth and potentially shrink the tumor.

Radiation can be delivered via radiosurgery or fractionated radiotherapy. In radiosurgery, concentrated beams of radiation are aimed to the tumor in one large dose of radiation. The treatment session may last approximately an hour.

In fractionated radiotherapy, multiple small doses of radiation are administered over several weeks. Each treatment session may take 5 to 15 minutes. After both radiosurgery and fractionated radiotherapy, patients can typically go home the same day.

For patients with a small and incidentally found schwannoma, treatment may not be necessary. Since the schwannoma is benign and slow growing, it may be preferable to simply observe the tumor over time with periodic imaging scans.

This strategy avoids the potential risks and complications associated with other treatment options like surgery and radiation therapy. However, it carries the risk of tumor growth between imaging scans.

Additionally, just the thought of a tumor being present in your body can cause anxiety. This can intensify in the days leading up to your imaging appointments.

It is important to note that your preferences for treatment can be changed at any point in time. Communicate regularly with your medical team and do not hesitate to ask questions and seek their advice.

The prognosis for a benign schwannoma is typically excellent. Surgery is often curative, and most individuals go on to live their normal lives after treatment. Although most patients experience an improvement in symptoms, some unfortunately do not and will require physical therapy and medications to address these issues.

Recurrence, particularly after total removal, is rare. Regular follow-up MRI scans and appointments with your medical team will be important to ensure that the tumor does not return and that if it does, it can be promptly addressed.

In very rare cases, schwannomas may transform into a more aggressive and cancerous form and become malignant peripheral nerve sheath tumors (MPNST). This can occur particularly in individuals with certain genetic conditions such as neurofibromatosis or with a history of radiation therapy.

Malignant schwannomas tend to grow more rapidly and can spread to other parts of the body, making it difficult to treat. Regular monitoring is crucial for managing schwannomas and detecting any signs of malignant transformation early.

• Schwannomas are benign slow growing tumors that arise from Schwann cells.
• They can occur on any peripheral nerve, but are most commonly found on the vestibular nerve (vestibular schwannoma.)
• Surgery can be curative, with radiation therapy used in certain cases.
• Small asymptomatic tumors may be monitored over time.
• Schwannomas exhibit excellent survival outcomes, though in rare cases can recur or transform into a more malignant form of disease.

• Acoustic Neuroma Association
• Children's Tumor Foundation
• Neurofibromatosis Network
• American Brain Tumor Association