Peripheral nerve sheath tumors develop from the Schwann cells, which are a type of cell that covers the peripheral nerves. These tumors can be benign or malignant, although ~90% of such tumors are benign. Nerve sheath tumors include neurofibromas and schwannomas.

In dogs and cats, peripheral nerve sheath tumors of the skin are found in older animals. In cattle, they have a suspected genetic basis, may be multiple, can develop in both the young and old, and are generally an incidental finding at slaughter; they arise from the deep nerves of the thoracic wall and viscera, and cutaneous involvement is rare. Nerve sheath tumors may arise on any nerve in the body, including the cranial nerves, the spinal nerves, and the peripheral nerves (nerves outside the brain and spinal cord). At The Spine Hospital at The Neurological Institute of New York, we specialize in treating spinal nerve sheath tumors.