Schwannomas, also called neuromas or neurilemomas, are tumors that affect the Schwann cells. These are cells that form a sheath around nerves to provide support and protection so that the nerves can function normally. Schwannomas are most common in people aged between 20 and 50 years. They usually affect the cranial nerves, peripheral nervous system, or the nerve roots, but don’t affect the central nervous system comprising the brain and the spinal cord.
The nerve connecting the inner ear to the brain is a common site for schwannomas, in which case the condition is known as acoustic neuroma or vestibular schwannoma. Most schwannomas are benign or non-cancerous. However, a small percentage of the growths are cancerous. Cancerous schwannomas are classified as soft tissue sarcomas and usually affect the sciatic nerve in the legs, the sacral plexus group of nerves in the lower back, and the brachial plexus nerves in the forearm.
1. Symptoms of Schwannomas
It takes quite some time before any symptoms of schwannomas can appear. This is because, while schwannomas form around nerves, their effects only begin when they have grown large enough to put pressure on the nerves sheathed by the affected tissues. By this time, the tumors may be large enough to form visible bumps under the skin on the face, limbs, and the torso. The schwannomas may also cause pain, pins and needles sensations, numbness, and muscle pain in the body parts served by the affected nerves. It’s common for schwannomas to grow around the auditory vestibular nerve that connects the inner ear to the brain. Symptoms of such tumors include hearing problems, poor balance and coordination, and ringing in the ears.