A brain tumor is a group of abnormal cells in or near the brain
Both malignant and benign brain tumors can damage brain tissue. Either directly, by damaging nearby healthy cells or indirectly, as a consequence of inflammation / swelling / crowding. Confined to the space inside the bony skull, there is no room for expansion for a growing tumor, which puts pressure on and displaces brain tissue. This may cause various symptoms and problems, some of which may be life-threatening. E.g. can block cerebrospinal fluid flowing through the brain, increasing intracranial pressure and enlarging ventricles (hydroencephalus)
• A benign brain tumor: grows slowly, has distinct boundaries, and rarely spreads to nearby brain areas.
• A malignant brain tumor (i.e. Brain cancer): grows quickly, has irregular boundaries, and usually spreads to nearby brain areas, but rarely to organs outside the brain or spine.
Primary brain tumors: originate in brain tissue; can be either malignant (brain cancer) or benign. Primary brain cancer does not usually metastasize to areas outside the brain or spine.
Metastatic brain tumors: cancer cells in brain tumor have traveled from another location via the blood or lymph; nearly always malignant. Lung and breast cancers are the most common cancers that spread to the brain.
Tumor cells are analyzed under a microscope and graded according to: cell muliplication rate, extent of blood supply to cells, amount of necrosis (dead cancer cells) in the middle of the tumor, if the cells are confined and how different they are to normal cells.
Basically unknown, possibly environmental or genetic
Symptoms of a brain tumor include: headaches, nausea, vomiting, seizures, behavior changes, memory loss, and vision or hearing problems.
