A brain tumor is a mass or growth of abnormal cells in the brain. They can be benign (non-cancerous) or malignant (cancerous) and can originate from various types of cells in the brain. Brain tumors can cause a wide range of symptoms, depending on their size, location, and rate of growth. These symptoms can include headaches, seizures, vision problems, and changes in cognitive function, among others. Brain tumors are typically diagnosed using imaging tests such as CT or MRI scans, and may be treated with surgery, radiation therapy, and/or chemotherapy.