Diagnosis

Your doctor will run tests to find where a peripheral nerve tumor is located and what type of tumor it is.

Tests

You might undergo one or more of the following tests.

  • MRI. This is the preferred method for imaging peripheral nerve tumors. This scan uses a magnetic field and radio waves to produce a detailed 3D view of the nerves and surrounding tissue. It can help determine whether you have a tumor and whether the tumor is inside or outside the nerve.
  • CT scan. A CT scanner rotates around the body to record a series of images. This test is not as useful as an MRI in diagnosing a peripheral nerve tumor. However, your health care provider might recommend it if you can't have an MRI or if more information regarding the nearby bone is needed.
  • Electromyogram (EMG). This test records the electrical activity in a muscle when you try to move it. It is used to help locate the tumor and identify which nerves are involved.
  • Nerve conduction study. You're likely to have this test along with your EMG. It measures how quickly your nerves carry electrical signals to your muscles.
  • Tumor biopsy. If imaging tests identify a nerve tumor, your care provider might remove and analyze a small sample of cells (biopsy) from your tumor. Depending on the tumor's size and location, you might need local or general anesthesia during the biopsy. The biopsy might be done with a needle with the help of imaging, or it might be done during surgery.
  • Nerve biopsy. To help diagnose the type of tumor, your health care provider may take a nerve biopsy. This involves taking a small sample of the tissue and sending it to a lab, where it's studied to look for signs of cancer.

Treatment

Treatment of peripheral nerve tumors involves either surgical removal or observation.

If there's a low likelihood that the tumor may become cancerous and if it isn't causing you problems, you might not need surgery.

Your health care provider might recommend observation if your tumor is in a place that makes removal difficult. Observation includes regular checkups and imaging tests to see if the tumor is growing.

Surgery may be needed if there is a concern that the tumor is cancerous. The tumor also may be surgically removed if it is large or causing pain or other symptoms, such as weakness, numbness or tingling.

Preparing for your appointment

You might be referred to a neurologist or neurosurgeon. A neurologist specializes in disorders of the nervous system. A neurosurgeon is trained in brain and nervous system surgery.

Here's some information to help you get ready for your appointment, and to know what to expect.

What you can do

  • Write down when you first noticed the problem and whether it has changed with time.
  • Write down your key medical information, including any surgeries.
  • Make a list of all your medications, vitamins or supplements.
  • Find out if anyone in your family has ever had similar problems.
  • Ask a family member or friend to accompany you, to help you remember what you learn during the appointment.
  • Write down questions to ask during the appointment.

Questions to ask your doctor

  • What's the most likely cause of the problem?
  • What kinds of tests do I need?
  • What treatments are available?
  • I have other health conditions. How can I best manage them together?

In addition to asking questions you've prepared, don't hesitate to ask other questions that come up during your appointment.

What to expect from your doctor

Your health care provider is likely to ask you a number of questions. Being ready to answer them may make time to go over points you want to discuss in-depth. You might be asked:

  • Do you have pain? Where is it?
  • Do you have any weakness, numbness or tingling?
  • Have your symptoms been continuous or occasional?
  • What treatments have you tried already for these problems?

Benign peripheral nerve tumor care at Mayo Clinic

Oct. 19, 2022
  1. Quinones-Hinojosa A, et al., eds. Peripheral nerve tumors of the extremities. In: Schmidek & Sweet: Operative Neurosurgical Techniques. 7th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed Aug. 20, 2022.
  2. Gilchrist JM, et al. Peripheral nerve tumors. https://www.uptodate.com/contents/search. Accessed Aug. 20, 2022.
  3. Jankovic J, et al., eds. Primary nervous system tumors in adults. In: Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed Aug. 20, 2022.
  4. Goldblum JR, et al. Benign tumors of peripheral nerves. In: Enzinger and Weiss's Soft Tissue Tumors. 7th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Aug. 20, 2022.
  5. Neurofibromatosis 1. National Organization for Rare Disorders. https://rarediseases.org/rare-diseases/neurofibromatosis-type-1-nf1/. Accessed Aug. 20, 2022.
  6. Lipoma. American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/diseases--conditions/lipoma. Accessed Aug. 20, 2022.
  7. Gupta VK, et al. Vestibular schwannoma: What we know and where we are heading. Head and Neck Pathology. 2020; doi.org/10.1007/s12105-020-01155-x.
  8. Kokkalis ZT, et al. Benign peripheral nerve tumors. Injury. 2019; doi.org/10.1016/j.injury.2019.10.054.
  9. Ask Mayo Expert. Neurofibromatosis 1. Mayo Clinic; 2021.
  10. Ami TR. Allscripts EPSi. Mayo Clinic. July 13, 2022.
  11. Spinner RJ (expert opinion). Mayo Clinic. Sept. 26, 2022.