A nervous system tumor is a

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

that arises within the

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

, either the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

(CNS) or the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of Bilateria, bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside t ...

(PNS). Nervous system

primary tumor A primary tumor is a tumor growing at the anatomical site where tumor progression began and proceeded to yield a cancerous mass. Most solid cancers develop at their primary site but may then go on to metastasize or spread to other parts of the b ...

s include various types of

brain tumor A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the Human brain, brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign ...

and spinal tumors, such as

glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...

s, and meningiomas (of the CNS), and schwannomas (of the PNS) and can be either

benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

. There are over 120 types of brain and spinal cord tumors. In the CNS a tumor may be a malignant secondary tumor having metastasised (spread from a primary site in the body). Secondary tumors are more common in adults. Treatment and prognosis depend on factors such as the type of tumor, location, and molecular characteristics.

Types

Primary tumor A primary tumor is a tumor growing at the anatomical site where tumor progression began and proceeded to yield a cancerous mass. Most solid cancers develop at their primary site but may then go on to metastasize or spread to other parts of the b ...

s can affect either the

(PNS) or the

(CNS). They may be either benign or malignant. A nerve sheath tumor may be found in both the CNS and PNS. There are over 120 types of brain and spinal cord tumor. A secondary tumor may be found in the CNS that has spread from another part of the body.

In the CNS

Primary tumors in the CNS originate within the brain or spinal cord. Some common types include: *

Glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...

s: Tumors arising from glial cells, which support and protect

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s. Subtypes are

astrocytoma Astrocytoma is a type of brain tumor. Astrocytomas (also astrocytomata) originate from a specific kind of star-shaped glial cell in the cerebrum called an astrocyte. This type of tumor does not usually spread outside the brain and spinal cord, an ...

s (from

astrocyte Astrocytes (from Ancient Greek , , "star" and , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of en ...

s),

oligodendroglioma Oligodendrogliomas are a type of glioma that are believed to originate from the oligodendrocytes of the brain or from a oligodendrocyte progenitor cell, glial precursor cell. They occur primarily in adults (9.4% of all primary brain and central ne ...

s (from

oligodendrocyte Oligodendrocytes (), also known as oligodendroglia, are a type of neuroglia whose main function is to provide the myelin sheath to neuronal axons in the central nervous system (CNS). Myelination gives metabolic support to, and insulates the axons ...

s), and

glioblastoma Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has a very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nons ...

s (thought to derive from astrocytes). * Meningiomas: Tumors that develop in the

meninges In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid spac ...

, the protective membranes covering the brain and spinal cord. These are typically benign and more common in adults. * Medulloblastomas: Malignant tumors that commonly occur in the

cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

, most often in children. * Ependymomas: Tumors that arise from the ependymal cells lining the ventricles of the brain and the central canal of the spinal cord.

In the PNS

Primary tumors in the PNS originate in the peripheral nerves and nerve sheaths. These tumors are often benign but can sometimes be malignant. Common types of nerve sheath tumors include: * Schwannomas: Benign tumors arising from

Schwann cell Schwann cells or neurolemmocytes (named after German physiologist Theodor Schwann) are the principal glia of the peripheral nervous system (PNS). Glial cells function to support neurons and in the PNS, also include Satellite glial cell, satellite ...

s, which produce the

myelin sheath Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ...

surrounding peripheral nerves. A common subtype is the vestibular schwannoma (acoustic neuroma). They only extremely rarely become malignant. * Neurofibromas: Benign tumors that grow on nerves, commonly associated with neurofibromatosis type I (NF1). * Malignant peripheral nerve sheath tumors (MPNSTs): Rare but aggressive cancers that arise from peripheral nerves or nerve sheath cells.

Secondary tumors

Secondary tumors in the CNS, or metastatic tumors, occur when cancer cells spread to the brain or spinal cord from a primary tumor in another part of the body. These tumors are more common than primary CNS tumors in adults and often originate from

cancers Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

of the

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

breast The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryology, embryological tissues. The relative size and development of the breasts is ...

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

, or colon.

Diagnosis

Diagnosis typically begins with a comprehensive medical history, and a neurological examination. The goal of the evaluation is to identify any neurological changes that may suggest the presence of a tumor. The assessment considers factors such as the nature, progression, and duration of the presented symptoms. Nervous system tumors can have a wide range of presentations, and a clinical evaluation is often followed by

neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the neuroanatomy, structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive ...

to confirm or rule out the presence of a tumor. Further testing, such as a

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, an interventional radiologist, or an interventional cardiology, interventional cardiologist. The process involves the extraction of sampling (medicine), sample ...

, may be necessary to determine the tumor type and grade.

Imaging

Advances in

imaging technologies Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materials and methods to create, preserve, or duplicate images. ...

, and

molecular diagnostics Molecular diagnostics is a collection of techniques used to analyze biological markers in the genome and proteome, and how their cells express their genes as proteins, applying molecular biology to medical tests, medical testing. In medicine th ...

, have significantly improved the accuracy of diagnoses in the CNS, and made possible effective targeted therapies.

Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(MRI) with contrast is the primary imaging modality for diagnosing brain and spinal cord tumors due to its high-resolution visualization of soft tissues. MRI helps identify the tumor's location, size, and potential impact on surrounding structures. In emergency situations or when MRI is contraindicated, a

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

can be used as an alternative. Additional imaging techniques can provide further insights. * Magnetic resonance spectroscopy (MRS) analyzes the chemical composition of brain tissue to differentiate tumors from non-neoplastic conditions such as infections or demyelinating diseases. *

Positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, r ...

(PET) assesses metabolic activity and can distinguish between tumor recurrence and treatment-related changes. * Diffusion tensor imaging (DTI) maps white matter tracts and helps plan surgeries to avoid critical brain regions.

Biopsy

A definitive diagnosis often requires a

tissue biopsy A biopsy is a medical test commonly performed by a surgeon, an interventional radiologist, or an interventional cardiologist. The process involves the extraction of sample cells or tissues for examination to determine the presence or extent o ...

. The biopsy can be performed through an open surgical procedure or minimally invasive

stereotactic surgery Stereotactic surgery is a minimally invasive form of surgery, surgical intervention that makes use of a three-dimensional coordinates, coordinate system to locate small targets inside the body and to perform on them some action such as ablation, ...

. Histopathological examination determines the tumor type, grade, and molecular characteristics, which are critical for guiding treatment decisions. In some cases, a liquid biopsy by way of a lumbar puncture (spinal tap) may be performed to analyze

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ven ...

(CSF). This can help detect tumor cells, especially in cases of suspected brain tumor metastasis, or primary CNS

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). The name typically refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph node ...

. The presence of tumor markers or abnormal cells in the CSF can provide diagnostic information that complements imaging and biopsy findings. Advances in

allow for the identification of genetic and molecular markers, improving the precision of tumor classification and enabling targeted therapies.

Epidemiology

Nervous system neoplasms vary in incidence and type based on factors such as age, tumor origin, and malignancy. Overall, brain and spinal tumors are more common in females due to the higher prevalence of meningiomas. Gliomas are the most common malignant brain tumor accounting for approximately 81% of malignant brain tumors and 26% of all brain tumors They are the most common brain tumor in children up to 14 years (25.7%), the next most commonly found are pilocytic astrocytomas (17.5%), and embryonal tumors (15.7%). The overall incidence rate of brain tumors in children is 6.2 per 100,000.

Glioblastoma Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has a very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nons ...

s are the most aggressive malignant glioma and make up approximately 47.7% of all

s, and are more commonly found in males. Their incidence rate is 3.23 per 100,000 people. The 5-year survival rate for glioblastoma is only 6.8%. Meningiomas, which develop in the meninges, are common brain tumors, representing approximately 37% of all brain tumors. The incidence rate for meningiomas is 9.51 per 100,000 people. Unlike gliomas, more than 98% of meningiomas are benign. The 5-year survival rate for nonmalignant meningiomas is approximately 91%. The distribution and behavior of nervous system neoplasms differ significantly between adults and children. Gliomas are more frequent and aggressive in adults, while certain benign tumors like pilocytic astrocytomas are more common in children. Notably, adults are more likely to develop secondary (metastatic) tumors that spread to the nervous system from cancers originating in other parts of the body.

References

External links

{{Central nervous system tumors Nervous system neoplasia