Types of Primary Brain tumor

They are four stages of primary brain tumors.

Grade 1. The tissue is benign. The cells look nearly like abnormal brain cells and cell growth is slow.
Grade 2. The tissue is malignant.The cells look like normal cells than do the cells in a grade 1 tumor.
Grade 3. The malignant tissues has cells look that very different from normal cells. The abnormal cells are actively growing. These cells are termed anaplastic.
Grade 4. The Malignant tissue has cells that look most abnormal and tend to grow very fast.