“Brain tumors” is a general term that includes both benignant and malignant tumors. They are growths of tissue in various parts of the central nervous system and depending on the genetics and the location of the tumors, they are given several classifications. There are more than one hundred types of brain tumors, and only some of them are malignant. It is important to know about the most common types of brain tumor, and which ones are malignant, mainly because only 33.2% of patients with brain cancer are reported to survive after 5 years in the United States.
In this article, you will be presented with the general terms doctors use to talk about brain tumors, the most common types of brain tumors in general, and the most common among children and adolescents. It is not meant to be a self-diagnose guide but instead a source of helpful information to understand why is there so much variety of brain tumors, and which ones are malignant.
Types and grades of brain tumors
The first thing we need to highlight is that brain tumors is not the same as brain cancer. Tumors can be benign or malignant depending on the alterations found in the cells that make up the cellular growth. So, our first classification of tumors is as follows:
- Benign brain tumors: They often experience slow growth and give out symptoms because they compress nearby structures. They are usually removed, and most of them will not grow back. They have a clear border and do not spread to other areas of the body. Benign brain tumors can be life-threatening depending on the area of the brain they are affecting.
- Malignant brain tumors: They contain cancer cells, which grow rapidly and uncontrollably, invade nearby tissues and may spread to other parts of the nervous system. However, even malignant tumors rarely spread outside the central nervous system. They are a threat to life, and some of them are very difficult to control.
We can also sort brain tumors by grades. The grades of the tumor depend on how abnormal cells look under the microscope. As they become more dangerous, cells would get a higher grade. Thus, we have the following grades:
- Grade I: The cells are very similar to normal brain cells. They have slow growth, and they are considered benign tumors.
- Grade II: There are more alterations in the cells, just enough to say the tissue has become malignant, but they still grow slowly.
- Grade III: The cells look different from healthy tissue, and they are continually growing. It’s a malignant tissue with uncontrolled proliferation (Anaplastic carcinoma)
- Grade IV: The cancerous cells are fast-growing, lose their identity and become entirely different from the original tissue.
Types of brain tumors
There are more than one hundred types of brain tumors, but here is a list of the most common sub-types:
These are the most common intracranial tumors. There are three different protective layers wrapping the brain and the spinal cord. They are called meninges, and the arachnoid is one of these membranes, resembling a spider web. Meningiomas are benign growths of arachnoid tissue, and even though they usually have slow growth, they may go unnoticed until they grow big enough to cause alterations. Depending on their location, they would give out several types of signs and symptoms, and some of them might be life-threatening or disabling.