A schwannoma is a type of tumor that develops from Schwann cells, which are specialized cells that create the protective sheath around nerve fibers. These tumors are usually benign, meaning they are non-cancerous. They are slow-growing and can form in various parts of the nervous system.
Understanding Schwannomas
Schwannomas originate from Schwann cells. While these tumors are usually benign, their growth can still cause problems by putting pressure on nearby nerves or surrounding tissues. This compression can interfere with normal nerve function.
These tumors can occur anywhere in the body where Schwann cells are present. They are commonly found on cranial nerves, spinal nerves, and peripheral nerves throughout the limbs. Vestibular schwannomas, also known as acoustic neuromas, are a common type that forms on the nerve connecting the inner ear to the brain. Spinal schwannomas are also observed, though less frequently than vestibular schwannomas.
Recognizing the Signs
The symptoms of a schwannoma depend significantly on its location and size, as the tumor’s growth can compress or irritate surrounding nerves. Initially, symptoms may be subtle and progress slowly over time.
For vestibular schwannomas, which affect the vestibulocochlear nerve, common symptoms include hearing loss and tinnitus, a ringing or buzzing sensation. Individuals may also experience dizziness or balance issues. As the tumor enlarges, it can press on the trigeminal nerve, leading to facial numbness, or on the facial nerve, causing facial weakness or paralysis.
Spinal schwannomas, which grow on nerve roots within or near the spinal canal, can cause symptoms such as back pain. Individuals may also experience weakness, numbness, or tingling sensations in the arms or legs, depending on the affected nerve. Larger spinal schwannomas can lead to more severe issues like impaired bowel or bladder function, or even paralysis.
Peripheral nerve schwannomas, found in the limbs, often present as a palpable lump or swelling under the skin. This lump is painless at first. As the tumor grows, it may cause localized pain, tingling, numbness, or muscle weakness in the affected area.
Diagnosis and Treatment Approaches
Diagnosing a schwannoma begins with a comprehensive medical history review, a physical examination, and a neurological assessment. If a schwannoma is suspected, imaging tests are used to visualize the tumor. Magnetic Resonance Imaging (MRI) with contrast is a primary diagnostic tool, providing detailed views of nerves and surrounding tissues. Computed Tomography (CT) scans can also be used to assess any associated bone changes.
Other diagnostic tests may include electromyography (EMG) and nerve conduction studies, which measure the electrical activity and signal speed in nerves and muscles. A tumor biopsy is performed to confirm the diagnosis, especially if imaging results are not conclusive. Biopsies can also help determine if the tumor is malignant, though this is rare.
Treatment options for schwannomas vary based on the tumor’s size, location, and the presence and severity of symptoms. For small, slow-growing tumors that are not causing significant symptoms, a “watch and wait” approach may be recommended. This involves regular monitoring with follow-up MRI scans every 6 to 12 months, to track any changes in tumor size or new symptom development.
Surgical removal is the preferred treatment for schwannomas that are large, growing, or causing noticeable symptoms like pain, numbness, or weakness. The goal of surgery is to remove the entire tumor while preserving nerve function as much as possible. Microsurgical techniques help surgeons differentiate between tumor tissue and healthy nerve fibers. Recovery varies depending on the tumor’s location and surgical complexity, ranging from same-day discharge to a few days in the hospital.
Radiation therapy, specifically stereotactic radiosurgery (SRS), offers a non-invasive alternative for tumors that are difficult to access surgically or for patients who are not suitable surgical candidates. SRS delivers highly targeted radiation beams to the tumor, aiming to stop its growth rather than remove it. This method is often used in a single treatment session or in a few fractions. While SRS can effectively control tumor growth, it does not eliminate the tumor.
Living with a Schwannoma
The long-term outlook for individuals with schwannomas is favorable. Following diagnosis and treatment, ongoing follow-up care is an important aspect of management. This involves regular clinical evaluations and repeat imaging, such as MRI scans, to monitor for any signs of tumor recurrence or continued growth.
While complete surgical removal provides a lasting solution, recurrence can occur if a portion of the tumor remains after surgery. Recurrences can happen even many years after initial treatment, highlighting the need for long-term surveillance. Even after treatment, some individuals may experience residual effects depending on the tumor’s original location and the impact of treatment. Hearing loss or facial weakness can persist after treatment for vestibular schwannomas. Most individuals with schwannomas can maintain a good quality of life.