Types of Brain Tumours; Benign or Malignant
Medikoe Health Expert
Koramangala, bengaluru, karnataka, india, Bengaluru Feb 9, 2017
A brain tumour is the growth of abnormal cells in any part of the brain or spinal cord. Brain tumours can be very harmful and may cause brain functions to disrupt, but it may also not be harmful.
Brain tumours can be benign or malignant. Benign tumours, the mass or abnormal cell, do not spread to other parts of the brain or body and are around the growth site, while malignant tumours are much more harmful, as it has cancer cells causing it to spread rapidly to other parts of the brain. Malignant tumours have no definite borders and are less common than benign tumours.
Both benign and malignant tumours could cause brain damage that could be fatal as they cause the pressure inside the skull to increase.
The World Health Organisation has identified more than 130 different types of brain tumours. But brain tumours are broadly classified into two types - Primary Tumours and Secondary or Metastatic Tumours.
Primary tumours are tumours that start in the brain and may spread to other parts. Although most of the tumours that originate in the brain or spinal cord rarely spread to other parts of the body. But they do spread to the nearby areas of the brain and destroy healthy tissue. This is why they need to be removed or destroyed immediately.
Secondary or metastatic tumours are tumours that have started in other organs but have spread to the brain. Secondary tumours are more common than primary tumours in adults.
Secondary and primary tumours are treated using different approaches and not the same.
Primary Brain Tumours
Primary tumours usually originate in the brain and are mostly benign, but can also be malignant. These tumours can develop from
The surrounding membranes around the brain called meninges
any type of tissue or cell in the spinal cord
Tumours may differ based on the areas of the central nervous system it affects, and hence the treatment approaches may vary.
Brain tumours are divided into four grades based on the appearances of the cells.
Grade I: The kind of tumours that do no spread rapidly as their growth is really slow. They tend to be benign and can be treated with surgery.
Grade II: These tumour cells also have slow growth, but unlike Grade I, they tend to affect the nearby brain tissue. These tumours may return even after surgery. With time their growth rate increases, thus making them harmful.
Grade III: When observed under the microscope, they appear more abnormal than other tumour cells. Lik Grade II tumours, they spread into neighbouring brain tissue. These tumours cannot be treated with surgery but may need additional treatments.
Grade IV: These tumours grow at a higher rate, and in fact, are the fastest-growing tumours. Treatment approaches concerning this tumour are very aggressive.
Secondary Brain Tumour
A secondary brain tumour does not originate in the brain and occurs when cancer cells from other organs like the heart, lungs, kidney, etc. spread to the brain. The spread of cancers within the body is called metastasis, which is why secondary tumours are also called a metastatic tumour. These tumours are malignant, as they have spread to different parts of the body and spreading rapidly.
Secondary brain tumours are named based on the origin of cancer. For example, if cancer originates in the breasts and spreads to the brain, it is still called breast cancer. This is because breast cancer means an abnormality in the cells in the breast and not in the brain cells.
Most brain tumours are secondary tumours.
People with secondary brain tumours have a low survival rate, but innovation in the field of medicine has helped increase the survival rates.
Types of Primary Tumours
The most common types of primary brain tumours are gliomas or glial tumours and non-glial tumours.
Gliomas are types of tumours that develop in the glial cells of the brain. These are the cells that do not produce any electrical impulses. The glial cells in the brain
Provide support to the structure of the central nervous system (part of the nervous system that includes the brain and spinal cord)
Provide nutrition to the central nervous system
Are crucial in the break down the dead neurons
Help clean cellular waste
There are mainly six types of tumours that occur in the glial cells of the brain. These are classified based on the histology of the tumour cells.
These are tumours that originate in the cerebrum and are usually benign. They originate in the astrocytes, which are star-shaped glial cells.
Astrocytomas tend to spread to different parts of the brain and blend with the brain tissues. This makes it hard to remove them with surgery. They only spread to different parts of the brain and spinal cord, but rarely outside the central nervous system.
In adults, astrocytomas originate in the cerebrum, while in children it usually originates from the brain stem, the cerebrum, and the cerebellum.
Astrocytomas are classified into four grades.
Non infiltrating or Grade I astrocytomas - They do not spread into the nearby brain tissues, and usually have a good prognosis. This type is more commonly found in children than adults
Low-grade or Grade II astrocytomas - They tend to grow slowly and might probably spread into nearby brain tissues, and could get more aggressive and fast-growing with time.
Anaplastic or Grade III astrocytomas - They tend to grow more quickly.
Glioblastomas or Grade IV - These tumours are very fast-growing and are the most common gliomas that occur in adults. They originate from the supportive brain tissue. They tend to affect adults more than children.
These kinds of gliomas are usually found in the frontal temporal lobe of the brain. They originate in oligodendrocytes, which are cells that produce myelin, a fatty covering that provides support and insulation nerves. These tumours do not tend to spread to neighbouring brain tissues that often.
Oligodendrogliomas are Grade II tumours that may sometimes spread to the surrounding tissues, and since they blend into these tissues, it is hard to remove them using surgery.
These are gliomas that usually develop in the ependymal cells, which are cells that line the ventricles and help with the production of cerebrospinal fluid(CSF). These tumours are mostly found in children than adults but can develop at any age. They are usually Grade II or Grade III tumours.
They usually spread across the CSF pathways, but rarely spread outside the brain or spinal cord. They do not blend with the brain tissues; hence it is easy to remove some ependymomas using surgery. But surgery might tend to cause nerve damage in some cases as these tumours tend to spread along ependymal.
4. Brain Stem Gliomas
They are also known as diffuse infiltrating brainstem gliomas, or DIPGs, are usually found in the brain stem. These tumours occur in children and adolescents and are rare but responsible for a lot of childhood deaths.
It is quite difficult to remove these tumours surgically as they are usually found in remote locations of the brain blended with healthy brain tissues which could affect the delicate and complex functions this area controls.
5. Optic pathway gliomas
These are the tumours that occur in the optic nerves or optic chiasm. This type of tumour could affect your vision or cause hormonal problems as they often originate at the base of the brain, part of the brain that works on hormone regulation.
6. Mixed Gliomas or Oligo-astrocytomas
They are usually made of more than one type of glial cells.
Non-glial tumours - There are other forms of primary tumours beside gliomas. They occur in the non-glial cells. A few common ones are discussed below.
Meningiomas- Meningioma, as the name suggests, begin in the meninges, which are tissues that surround the outer part of the brain and spinal cord. They are one of the most commonly occurring forms of brain tumour.
Meningiomas are usually benign and don't cause any symptoms until it has grown to a large size. They are typically found in women between 30 and 50 years of age and sometimes run in families.
Medulloblastomas- These tumours develop from neuroectodermal cells, i.e. the early forms of nerve cells in the cerebellum. They are usually Grade IV tumours and spread rapidly throughout the CSF pathways and often require aggressive treatment.
Children are much more affected by medulloblastomas than adults.
Gangliogliomas- These kinds of tumours have both neurons and glial cells. They are Grade II tumours and aren't that common. They can be treated and cured by surgery on its own, and sometimes surgery along with radiation.
Schwannomas (neurilemmomas)- This form of brain tumour develops from Schwann cells, which are responsible for providing the nerves with insulation. They usually present as Grade I tumours and usually form on the cranial nerve or spinal nerves. Tumours occurring in the spinal nerves could cause weakness, loss of sensation, and problems in the bowel and bladder.
Craniopharyngiomas- These usually benign tumours occur at the base of the brain above the pituitary gland; it usually presses on the gland and hypothalamus, which could result in hormonal problems. These tumours sometimes get close to the optic nerves causing vision problems.
Although these are Grade I tumours, it is hard to treat them with surgery as they occur near essential structures in the brain, and there are chances that vision and hormonal balance could get damaged.
These tumours are more common in children and adolescents than adults.
Chordomas- These are very rare tumours that originate at the base of the skull or on the lower parts of the spine. These tumours could cause damage to the spinal cord or brain if they press on it.
Chordomas are usually treated using surgery coupled with radiation but tend to reoccur in the same region and cause worse damage than before.
Pituitary tumours- These are tumours that originate in the pituitary gland and are usually benign. But since the pituitary gland is responsible for hormone production and regulation, these tumours could bring severe problems if they accidentally press on regions that could stimulate the production of a hormone more than necessary.
Treatment of Brain tumour
Brain tumour, like most other forms of tumour or cancer, is treated based on the type of tumour, the extent it has spread, and the area it has affected. Based on all this, the doctor may treat it with one of the following options or a combination of these.
Surgery - This form of treatment is removing the tumour surgically. The tumour is either partially or entirely removed based on the area it affects. There are chances of cancer returning even after surgery.
Radiation therapy - This form of treatment is usually coupled with surgery. It involves treating cancer with harmful radiation that stops its development and growth. The patient is given radiation from an external source, or radioactive seeds are placed in or around the region affected with cancer.
Chemotherapy - This form of treatment uses powerful drugs and chemicals to stop the growth of cancer or tumour cells. It is administered into the body through the mouth, Intravenously(IV) or placed in the brain by the surgeon using wafers.
Targeted therapy - This form of treatment makes use of certain types of drugs that attack specific parts of the cancer cells and inhibit its growth and development. This form of therapy is still being researched, and as of now, it is only effective in treating only some kinds of tumours.
If you are a person diagnosed with a brain tumour, it is crucial to take your visits to the doctor seriously and follow everything the doctor says.
Are you looking for a health expert around you?
Medikoe is an online platform that allows you to search and connect with the most qualified and experienced doctors near you. Have a query related to health? Get it answered for free within 24 hours only at Medikoe. Download Medikoe's Mobile app and book an appointment with a doctor for free.