Schwannomas -- also known as acoustic neuromas -- are tumors that begin in the Schwann cells in the nerve sheaths of cranial nerves in the brain. They are usually benign, non-aggressive and curable. Schwannomas can affect both adults and young people: they account for just under 10 percent of central nervous system tumors in adults, but are rare in children.
When these tumors form near the cerebellum, in the cranial nerve responsible for hearing and balance, they are referred to as vestibular schwannomas. They can also grow in spinal nerves outside of the spinal cord, where they often compress the spinal cord, and lead to weakness, sensory loss, and bowel and bladder problems.
When schwannomas do arise in children, their presence usually indicates a condition such as neurofibromatosis, a disease that results in benign tumors that form in nerves throughout the body. Neurofibromatosis is generally an inherited condition, but can also occur in patients with no family history.
There are few known risk factors for schwannomas. Lifestyle factors may play a role in adult, but not childhood, schwannomas, although no definitive link has been found. Prior radiation exposure to the head, normally during treatment for other conditions, is the only known risk factor.
There are no reliable blood tests or other screening exams for these tumors. Children at higher risk because of inherited syndromes are encouraged to have more frequent medical checkups.
Brain and spinal cord tumor symptoms may develop gradually or appear suddenly. Symptoms associated with schwannoma are trouble with coordination (including walking or eating) if the tumor is in the cerebellum; hearing loss, balance issues and facial muscle weakness if the tumor is near the cranial nerves. Some schwannomas that compress the brain may cause facial pain. Any of these symptoms can also be indicative of other conditions but should be checked out.
If a schwannoma is discovered -- usually through an imaging test like MRI or a CT scan -- surgery or radiation therapy are commonly used depending on tumor location and other factors. Chemotherapy is not generally useful for treating schwannomas.