Learn all about Schwannomas. A schwannoma is a spinal tumor that arises from the lining of the nerve cells of the spine
A schwannoma develops from cells called Schwann cells, a cell that wraps itself around peripheral nerves and provides protection and support. Schwannomas are almost always benign (not cancerous), but rarely, may become cancerous (a malignant schwannoma).
The nerves of the spine are insulated by a protective sheath called myelin, which transmits nerve impulses throughout the body. Schwann cells create the myelin sheath of the nerves. A schwannoma is a tumor of the peripheral nervous system or nerve root.
When a schwannoma tumor develops, it forms around the tissue of the myelin sheath. Most schwannomas are benign, only 2.5 percent are cancerous.
Nerve sheath tumors can be associated with genetic disorders such as neurofibromatosis and schwannomatosis. There is great variation in terms of tumor location, clinical presentation and treatment strategy. Magnetic resonance imaging is the diagnostic study of choice for nerve sheath tumors and surgery has become the mainstay of treatment for most symptomatic lesions.
Schwannomas Symptoms and Treatment
Schwannomas usually don’t produce symptoms until they become large enough to put pressure on the nerves around them. You may feel occasional pain in the area that’s controlled by the affected nerve. Schwannomas are usually removed with surgery. They can often be scraped off without damaging the nerve. Your recovery time and any remaining symptoms can vary widely based on the size and location of the schwannoma. In the vast majority of spinal schwannomas, the tumors can be entirely removed without causing neurological problems.
Nerve tumors can form in the peripheral nerve network anywhere in the body. These tumors often affect the function of the nerve, causing pain and disability. A large majority of peripheral nerve tumors are benign (not cancerous). Some are caused by neurofibromatosis, or schwannomatosis (genetic disorders of the nervous system). Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. The nervous system consists of the brain, spinal cord, and the nerves that reach out from them to all areas of the body. The nervous system is essential for thinking, sensation, and movement, among other things.
Peripheral Nerve Sheath Tumor (PNST)
Peripheral nerve sheath tumours (PNSTs) are a group of primary neurogenic tumours that arise from nerve sheaths outside of the central nervous system. The vast majority are benign, however, malignant transformation is seen particularly in large tumours and those associated with neurofibromatosis type 1 (NF1). Peripheral nerves receive messages from the central nervous system (the brain and spinal cord) that stimulate voluntary movement. Peripheral nerve sheath tumors can develop along any of these nerves in the head or neck or arise on the nerves before they exit the skull. They can also grow along the length of the nerve outside the skull, which can cause the nerve to malfunction.
Schwannoma symptoms may include:
- a visible lump under the skin
- sharp, aching, or burning pain
- a pins-and-needles sensation
- muscle weakness
- nighttime pain in back or neck
- Back pain that worsens when lying down
- Tingling sensations
- Pain that radiates through the legs.
- To diagnose a schwannoma, doctor may ask about signs and symptoms, discuss your medical history, and perform both a general physical and neurological exam. Other diagnostic tests are:
- Magnetic resonance imaging (MRI); This scan uses a magnet and radio waves to produce a detailed, 3-D view of 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, 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
- 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
Schwannoma treatment may depend on the location of the tumor and whether the tumor is benign or malignant (cancerous). A benign schwannoma is typically treated with surgery to remove as much as the tumor as possible while keeping the affected nerve intact. It is often possible to remove the entire tumor. People who have surgery for a benign schwannoma usually have fast relief of symptoms. UPMC neurosurgeons typically perform microsurgery to remove the tumor if the patient experiences symptoms such as weakness, numbness, or pain.
Using a microscope and intraoperative electrophysiological monitoring, surgeons open the nerve and carefully remove the tumor. For large tumors, radiation and chemotherapy may be used in conjunction with surgery. Spinal schwannomas may also be treated with stereotactic spine radiosurgery, which is a minimally invasive technique that uses highly focused beams of radiation to target spinal tumors. The beams destroy the tissue that a surgeon would otherwise need to remove with a scalpel during a traditional operation. The precision of this surgery results in minimal damage to the healthy tissue surrounding the tumor, and no recovery time.
Schwannoma surgery is it’s the primary treatment. However, in the case of major peripheral nerves with motor function, there are concerns including neurological complications following surgery. This study was designed to evaluate the surgical outcome of Schwannomas originating from major peripheral nerves of the lower limb. When surgically removing a spinal nerve schwannoma, preservation of the involved root is attempted and may be feasible. However, in large tumors, sacrifice of the nerve root is often required to achieve total removal of the tumor, and the resection does not always result in postoperative neurological deficit.