A mass created by growth of abnormal cells or uncontrolled proliferation of cells in the brain. Primary brain tumor includes any tumor that originates in the brain.
Tumors can directly destroy brain cells.
Classification of brain tumors depends on the exact site of the tumor, type of tissue involved, benign or malignant tendencies of the tumor, and other factors. They are 2nd in incidence , only surpassed by leukemias. Two-thirds of brain tumors in children are infratentorial with peak ages of 5 to 9 years. The annual incidence in children less than 15 years old is 2.4 per 100,000. More than 1,200 new cases occur each year.