Diagnosis

To diagnose a schwannoma, your doctor may ask you about signs and symptoms, discuss your medical history, and perform both a general physical and neurological exam. If signs suggest that you could have a schwannoma or other nerve tumor, your doctor may recommend one or more of these diagnostic tests:

• Magnetic resonance imaging (MRI). This scan uses a magnet and radio waves to produce a detailed, 3-D view of your nerves and surrounding tissue.
• Computerized tomography (CT). A CT scanner rotates around your body to record a series of images. A computer uses the images to make a detailed view of your growth so that your doctor can evaluate how it may be affecting you.
• Electromyogram (EMG). For this test, your doctor places small needles in your muscles so an electromyography instrument can record the electrical activity in your muscle as you try to move it.
• 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 doctor may remove and analyze a small sample of cells (biopsy) from your tumor. Depending on the tumor's size and location, you may need local or general anesthesia during the biopsy.
• Nerve biopsy. If you have a condition such as progressive peripheral neuropathy or enlarged nerves that mimic nerve tumors, your doctor may take a nerve biopsy.