A brain tumor, also referred to as an intracranial tumor, is an abnormal mass of tissue where cells proliferate and multiply uncontrollably, potentially evading the regulatory mechanisms typical of normal cells. There are two main categories of brain tumors: primary and metastatic.
Primary brain tumors originate from the tissues of the brain or its immediate surroundings. These primary tumors are classified as either glial (composed of glial cells) or non-glial, and they can be benign or malignant.
On the other hand, metastatic brain tumors develop elsewhere in the body (such as in the bones or lungs) and migrate to the brain, typically through the bloodstream. Metastatic tumors are considered cancerous and are malignant. Various types of metastatic brain tumors exist, each with its distinctive characteristics.