What are the types and causes of brain tumors?

A brain tumor is an abnormal growth of cells in the brain. Although this abnormal growth of cells is commonly referred to as a brain tumor, not all brain tumors are cancer. Cancer is a specific term for malignant tumors. So what are the types of brain tumors?

Types of Brain Tumors

1. Primary brain tumor

The brain is made up of many different types of cells. A brain tumor forms when one type of cell changes from its normal characteristics. Once the transformation occurs, the cells grow and proliferate in an abnormal way. These abnormal cells grow into a mass, or tumor.

Tumors formed by brain cells that change and grow in this abnormal way are called primary brain tumors because they originate in the brain tissue itself. The most common primary brain tumors include gliomas, meningiomas, pituitary adenomas, acoustic neuromas, and primitive neuroectodermal tumors (medulloblastomas). Gliomas include astrocytomas, oligodendrogliomas, ependymomas, and choroid plexus papilloma. Most brain tumors are named based on where they originate or the cells in which they originate.

2. Metastatic brain tumors

Metastatic brain tumors are caused by cancer cells from tumors elsewhere in the body spreading to the brain. The process by which cancer cells spread from other parts of the body to brain cells is called metastasis. About 25% of tumors elsewhere in the body metastasize to the brain.

Causes of Brain Tumors

Like tumors elsewhere in the body, the exact cause of brain tumors is unknown. Genetic factors, various environmental toxins, radiation, and smoking have all been associated with the development of brain tumors, but in most cases, no clear cause has been found.

Risk factors for primary brain tumors include: ① radiation to the head, ② special genetic constitution, and ③ human immunodeficiency virus (HIV) infection. However, whether these factors actually increase your risk of developing a brain tumor is uncertain.

Symptoms of a Brain Tumor

Not all brain tumors cause symptoms, and some (such as pituitary tumors) are often not discovered until after death. Symptoms of brain tumors are many and nonspecific, which means they can also occur with a variety of other diseases. The only way to know for sure what is causing the clinical symptoms is to do a diagnostic test.

Some symptoms occur because the tumor presses on or invades other parts of the brain, affecting the functioning of normal tissues. Some symptoms occur due to brain edema caused by inflammation of the tumor itself or its surrounding areas. Symptoms caused by primary brain tumors and brain metastases are similar.