Schwannoma
Encyclopedia
A schwannoma is a benign nerve sheath tumor
composed of Schwann cell
s, which normally produce the insulating myelin sheath covering peripheral nerves
.
Schwannomas are very homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow growing. For reasons not yet understood, schwannomas are mostly benign
and less than 1% become malignant, degenerating into a form of cancer
known as neurofibrosarcoma.
Schwannomas can arise from a genetic disorder called neurofibromatosis
. They are universally S-100
positive.
Schwannomas can be removed surgically, but can then recur.
Nerve sheath tumor
A nerve sheath tumor is a type of tumor of the nervous system which is made up primarily of the myelin surrounding nerves.A peripheral nerve sheath tumor is a nerve sheath tumor in the peripheral nervous system....
composed of Schwann cell
Schwann cell
Schwann cells or neurolemmocytes are the principal glia of the peripheral nervous system . Glial cells function to support neurons and in the PNS, also include satellite cells, olfactory ensheathing cells, enteric glia and glia that reside at sensory nerve endings, such as the Pacinian corpuscle...
s, which normally produce the insulating myelin sheath covering peripheral nerves
Peripheral nervous system
The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...
.
Schwannomas are very homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow growing. For reasons not yet understood, schwannomas are mostly benign
Benign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
and less than 1% become malignant, degenerating into a form of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
known as neurofibrosarcoma.
Schwannomas can arise from a genetic disorder called neurofibromatosis
Neurofibromatosis
Neurofibromatosis is a genetically-inherited disorder in which the nerve tissue grows tumors that may be benign or may cause serious damage by compressing nerves and other tissues...
. They are universally S-100
S-100 protein
S-100 protein is a family of low molecular weight protein found in vertebrates characterized by two calcium binding sites of the helix-loop-helix conformation. There are at least 21 different types of S100 proteins...
positive.
Schwannomas can be removed surgically, but can then recur.
See also
- NeurofibromaNeurofibromaA neurofibroma is a benign nerve sheath tumor in the peripheral nervous system. Usually found in individuals with neurofibromatosis type I , an autosomal dominant genetically-inherited disease, they can result in a range of symptoms from physical disfiguration and pain to cognitive disability...
- Vestibular schwannoma (Acoustic neuroma)