Brain cancer is caused by abnormal growths of cells in the brain. Brain cancers can start from primary brain cells, from the cells that make other brain components, or from the expansion of cancer cells from other organs that have extend to the brain by the bloodstream.

Malignant tumors develop and multiply insistently, subduing healthy cells by acquiring their space, blood, as well as nutrients. This is particularly an issue in the brain, as the additional expansion within the closed limits of the cranium can cause a raise in intracranial stress or the deformation of adjoining critical structures, leading to their break down.

Tumors that do not grow insistently are known as benign. More or less all tumors that start in the brain do not extend to other parts of the body. The key distinction amid benign and malignant tumors is that malignant tumors can enter into the brain tissues and quickly grow.

In most cases, a benign tumor is not as grave as a malignant tumor. Nonetheless, a benign tumor can become the source of several problems within the brain.

Primary brain tumors

The brain is formed by several different kinds of cells. Cancers occur as one type of cell alters and changes its usual traits. Once altered, the cells develop and increase in abnormal means. When these abnormal cells grow, they are converted into an accumulation of cells, known as tumor.

Brain tumors that occur from this alteration and abnormal development of brain cells are termed as primary brain tumors as they start in the brain.

Brain tumors differ in their growth speed as well as capacity to show warning signs. To find out severity, tumors are categorized by using a grading system;

1. Grade I: The tissue becomes benign. The cells seem almost similar to normal brain cells, and cell growth is not fast.
2. Grade II: The tissue becomes malignant. The cells seem less similar normal cells as compared to the cells in a 'Grade I' tumor.
3. Grade III: The malignant tissue contains cells that appear significantly different from normal cells. The abnormal cells are rapidly growing. These rapidly growing cells are known as anaplastic.
4. Grade IV: The malignant tissue contains cells that appear to be very abnormal and are likely to grow very rapidly.

Metastatic brain tumors

Metastatic brain tumors are the cancerous cells that reach other parts via the bloodstream from a tumor traced somewhere else in the body. The cells reach the brain from another tumor by a method called metastasis. Generally, the flow of blood in brain shows where the metastatic cancer cells are present.