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A nervous system tumor is a tumor that arises within the nervous system, either the central nervous system (CNS) or the peripheral nervous system (PNS). [1] [2] Nervous system primary tumors include various types of brain tumor and spinal tumors, such as gliomas, and meningiomas (of the CNS), and schwannomas (of the PNS) and can be either benign or malignant.
Ganglioneuroma (occasionally called a "ganglioma") is a rare and benign tumor of the autonomic nerve fibers arising from neural crest sympathogonia (undifferentiated cells of the sympathetic nervous system). [1] However, ganglioneuromas themselves are fully differentiated neuronal tumors that do not contain immature elements. [2]
Neuromas tend to be benign (i.e. not cancerous); many nerve tumors, including those that are commonly malignant, are nowadays referred to by other terms. Neuromas can arise from different types of nervous tissue, including the nerve fibers and their myelin sheath, as in the case of genuine neoplasms (growths) like ganglioneuromas and neurinomas.
In children aged 0–14 years, the most common brain tumors are pilocytic astrocytomas (17.5%), embryonal tumors (15.7%), and malignant gliomas (25.7%). [15] The overall incidence rate of brain tumors in children is 6.2 per 100,000. [9] The distribution and behavior of nervous system neoplasms differ significantly between adults and children.
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. These masses are generally contained within a capsule, so surgical removal is often successful. [3]
For the concepts of benign and malignant neoplasia see Tumor and Cancer. For primary and secondary neoplasias see Metastasis. A brain tumor composed of benign cells, but located in a vital area (as the brain is), can be considered to be life-threatening — although the tumor and its cells would not be classified as malignant. [4]
Gangliogliomas are generally benign WHO grade I tumors; the presence of anaplastic changes in the glial component is considered to represent WHO grade III (anaplastic ganglioglioma). Criteria for WHO grade II have been suggested, but are not established. Malignant transformation of spinal ganglioglioma has been seen in only a select few cases ...
A vestibular schwannoma (VS), also called acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve that passes from the inner ear to the brain. The tumor originates when Schwann cells that form the insulating myelin sheath on the nerve malfunction. Normally, Schwann cells function beneficially to protect the nerves which ...