Neurofibrosarcoma and Schwannoma

Written by Stephanie Watson, Marijke Vroomen Durning, RN
Medically Reviewed by Laura J. Martin, MD on February 28, 2025
8 min read

Schwannomas and neurofibrosarcomas are nerve sheath tumors, which means they involve the coating around nerves. A nerve consists of a bundle of nerve fibers. Nerves transmit messages between the brainand spinal cord and the rest of the body.

 

“Schwannomas are usually benign tumors arising from Schwann cells, which are the cells that form the cover around nerve fibers,” explained Erick M. Westbroek, MD, a neurosurgeon at Providence St. Jude Medical Center in Fullerton, CA.

Although schwannomas are generally not cancerous, they can cause problems if they grow. They can press on the nerves and surrounding tissues, causing nerve damage and difficulty controlling the affected muscles.

The tumors can form anywhere, but they often develop in the inner ear — which is called a vestibular schwannoma or an acoustic neuroma. If you have a vestibular schwannoma, it can affect your balance and hearing.

In rare cases, schwannomas can be cancerous. In these cases, they most often develop along the:

  • Sciatic nerve (from your back down to your leg)
  • Brachial plexus (nerves in your arm)
  • Sacral plexus (nerves in your lower back)

Most people who have a schwannoma are in their 50s or 60s. You might also hear a doctor call them neurilemmomas or neuromas.

Neurofibrosarcomas are rare, cancerous tumors. “A very small percentage of nerve sheath tumors are malignant," Westbroek says. 

Doctors only diagnose about 200 cases a year in the U.S. They form in the sheath that protects the peripheral nerves and are aggressive, meaning that they grow and spread quickly into blood vessels and lymph vessels.

Neurofibrosarcoma is also known by several other names, such as:

  • Malignant schwannoma 
  • Malignant neurofibroma
  • Malignant neurilemmoma
  • Malignant mesenchymoma of nerve sheath origin
  • Neurogenic sarcoma

Now, they are usually referred to as malignant peripheral nerve sheath tumors (MPNSTs).

These tumors can affect anyone, including older children and teens, but most people who get them are between 20 and 40 years old. Neurofibrosarcomas usually affect the arms or legs but can also affect the head, neck, chest, abdomen, pelvis, and back.

Schwannomas form in the tissue that surrounds and insulates nerves. They develop when Schwann cells -- the cells that form the covering around nerve fibers -- grow abnormally. Although schwannomas don’t spread, they can grow large enough to press down on important structures in the brain (including the brain stem).

Neurofibrosarcomas are more complex than schwannomas, and they can spread along the nerves. They typically don't reach other organs, although they can spread to the lungs. They can arise from Schwann cells, as well as other types of cells and tissue.

 

 

 

Mostly, doctors don’t know what causes nerve sheath tumors.

What causes a schwannoma tumor?

Doctors still don’t understand what causes about 90% of schwannomas. “Most schwannomas occur at random, but certain genetic conditions, such as neurofibromatosis type 2, can significantly increase the risk of developing schwannomas,” Westbroek says. “A related condition, neurofibromatosis type 1, is associated with a significantly increased risk of developing neurofibrosarcoma.”

What causes neurofibrosarcomas?

As with schwannomas, researchers still have to find out what causes most neurofibrosarcomas. What we do know is that  an inherited disorder known as neurofibromatosis type 1 (previously known as von Recklinghausen disease) is "associated with a significantly increased risk of developing neurofibrosarcoma,” according to Westbroek. “Radiation exposure is also associated with an increased risk of developing neurofibrosarcoma,” he says.

The symptoms of schwannoma and neurofibrosarcoma depend on where the tumor is, how large it is, and if it has spread.

Schwannoma symptoms

If you have a vestibular schwannoma, the symptoms are related to how the tumor is affecting the nerves in your inner ear and brain. It can cause:

  • Hearing loss on one side
  • A feeling of fullness in one ear
  • Dizziness
  • Loss of balance
  • Tinnitus (ringing or other type of noise in the ear)
  • Numbness in the face
  • Facial twitching
  • Facial weakness
  • Difficulty swallowing
  • Change in tear production
  • Headache and/or pressure in your head

Symptoms of a schwannoma in an arm or leg could include:

  • Pain in the affected limb
  • Weakness
  • Tingling or pins-and-needles feeling
  • Carpel tunnel syndrome
  • Tarsal tunnel syndrome

And if the schwannoma is in the back, it could cause:

  • Tingling
  • Pain
  • Weakness of the limb associated with the affected nerve
  • Bowel or bladder incontinence
  • Paralysis

Neurofibrosarcoma symptoms

Like with schwannomas, neurofibrosarcoma symptoms are related to where the tumor is. You may notice:

  • Weakness in the affected area
  • Changes to your sense of touch and pain
  • Pain or tingling where the tumor is
  • Changes in the temperature of the affected area
  • A noticeable lump

To see if you have a nerve sheath tumor, a physician will perform a physical and neurological (brain and nervous system) exam, according to Westbroek. “Imaging of the tumor, MRI or CT, will also be considered and a biopsy may be required to make a definitive diagnosis,” he says. The biopsy (removing a tissue sample and examining it in the lab) will tell you if the tumor is malignant.

 

How your doctor chooses to treat a nerve sheath tumor depends on if it’s malignant, where it is, and how it is affecting you.

Schwannoma treatment options

Schwannomas may not need treatment if they’re not causing any symptoms. However, your doctor will monitor it closely for changes. You might need surgery if the tumor is growing quickly or is pressing on a nerve, causing pain or other problems. 

In some cases, your doctor could recommend radiation therapy. This could happen if the tumor is too close to vital blood vessels or nerves and surgery could cause complications. Called stereotactic radiotherapy (SRS), this type of radiation focuses radiation beams on the tumor to destroy it. 

Schwannomas are rarely cancerous, but if they are malignant, the doctor may treat them with immunotherapy and chemotherapy, in addition to radiation or surgery.

Neurofibrosarcoma treatment options

Surgery. The most common treatment for neurofibrosarcomas is to remove them with surgery. Your doctor would remove the tumor and as much of the tissue around it as needed. Surgeons try to remove the tumor without damaging too much of the affected arm or leg (called limb-salvage or limb-sparing surgery). But if the tumor alone can't be removed, the arm or leg might need to be removed (amputated).

Radiation therapy. Radiation may be used in a few ways to treat neurofibrosarcoma: 

  • Before surgery to shrink the tumor, making it easier to remove
  • If the entire tumor couldn’t be removed
  • If there’s a chance there are cancer cells in your body

Chemotherapy. Like radiation, chemotherapy can also be an option in treating some neurofibrosarcomas:

  • To shrink the tumor before surgery
  • If the cancer has spread beyond the tumor to other parts of the body
  • To slow cancer growth and control symptoms

 

 

 

The prognosis and survival rates for nerve sheath tumors vary according to what type they are, how big they are, and how they respond to treatment.

Schwannoma prognosis

Generally, the prognosis and survival rates for schwannomas are good. “Schwannomas typically do not come back after being completely resected,” Westbroek says. However, the surgery itself may result in some lasting effects depending on where the tumor is. It can take a while for nerves to repair themselves after the surgery, and affected muscles may continue to be weak. If you have surgery for a vestibular schwannoma, you might have hearing problems, headaches, balance issues, or facial weakness for weeks or months.

Tumors that aren’t removed could press on nerves or other tissue, causing weakness. A vestibular schwannoma could lead to hearing loss.

Neurofibrosarcoma prognosis

The prognosis for neurofibrosarcomas is different than that for schwannomas, as these types of tumors are malignant. “Neurofibrosarcomas prognosis depends on many factors, such as tumor size, location, degree of spread throughout the body, and what treatments are used,” Westbroek says.

The five-year survival rate for this type of tumor (the percentage of people who are still alive five years after diagnosis) is between 23% and 69%. It’s a wide range because the prognosis depends on the size of the tumor, if the cancer was completely removed during surgery, or if the cancer spread.

Since doctors don’t know what causes most schwannomas and neurofibrosarcomas, there isn't a specific way to prevent them. There are a few risk factors for neurofibrosarcomas though. So, inform your doctor if you develop any symptoms and have risk factors such as:

  • Previous radiation therapy for cancer (neurofibrosarcoma could develop in the treated area 10 to 20 years later)
  • Presence of a noncancerous nerve tumor, such as a neurofibroma
  • A family history of neurofibromatosis

Schwannomas are most often noncancerous nerve tumors, while neurofibrosarcomas are cancerous. In most cases, doctors don’t know their exact cause although there might be some genetic connection in some cases. Schwannomas can press on nerves and body tissues, causing pain or other problems. If you have one, your doctor may want to remove it before it gets bigger. Neurofibrosarcomas are usually removed but because they are cancerous, you may need chemotherapy or radiation therapy as well.

What is the difference between a schwannoma and a neurofibrosarcoma?

A schwannoma is a tumor that comes from the Schwann cells and is rarely cancerous. Neurofibrosarcomas can come from Schwann cells but are often involved with other nerve cells too, and they are cancerous.

What is neurogenic tumor schwannoma?

“Neurogenic tumor schwannoma” isn’t a term used in the medical field. A neurogenic tumor is a tumor that arises in the cells of the nervous system. Neurogenic tumors can be schwannomas or neurofibrosarcomas.

What are the symptoms of schwannomas and neurofibrosarcomas?

Schwannomas and neurofibrosarcomas are nerve sheath tumors. 

Sometimes, schwannomas don’t come with symptoms; if symptoms occur, they may include:

  • Tingling or numbness
  • Weakness
  • Pain

Neurofibrosarcoma symptoms might include:

  • Weakness in the affected area
  • Changes in your sense of touch and pain
  • Pain or tingling in the affected area
  • Changes in the temperature of the affected area
  • A noticeable lump

Is a schwannoma considered cancer?

Most schwannomas are benign (not cancerous). About 5% of schwannomas can become cancerous.

How do you treat neurofibrosarcoma?

Neurofibrosarcoma treatment options include surgery, radiation therapy, and chemotherapy. Surgery may not be an option if the tumor has spread, if it’s too large, or if your doctor is concerned surgery could affect other close nerves. 

Is schwannoma life-threatening?

Most schwannomas are benign but can become life-threatening if they become large enough to press against parts of the brain that are close to the tumor.