Dushyant Verma Maharani Bagh - A brain tumor is a mass or growth of abnormal cells in the brain. Brain tumors can be benign (non-cancerous) or malignant (cancerous). Most brain tumors are benign, meaning they are not cancerous and do not grow or spread to other parts of the brain or body. However, some brain tumors can be malignant, meaning they are cancerous and can grow and spread to other parts of the brain or body.