Brain Tumor Awareness Week - Staging

Brain tumors are classified according to the WHO (World Health Organization) system.

Tumors are classified by observations made concerning the appearance of the cells, its tendency to infiltrate into other areas and, its rate of growth. The classification of brain tumors is primarily an observance by a neuro-pathologist and can be classified differently by two different pathologists. Therefore, classification is not always easily determined. Furthermore, a single tumor can have cells of multiple classifications. In this case, the entire tumor is classified as the highest discovered grade found.

Benign Tumors

Grade One

A grade one tumor has cells that are mostly normal in appearance. The cells are extremely slow growing and are even sometimes classified as a birthmark within the brain. The long term survival with a Grade One tumor is extremely good.

Grade Two

A grade two tumor has slightly more of an abnormal look but still appears mostly normal. This type of tumor has the potential to invade into other areas of the brain but are mostly of a slow growing type. A grade two has a much higher tendency of developing or recurring into a higher grade tumor.

Malignant Tumors

Grade Three

A grade three tumor is actively growing and comprises of mostly abnormal cells. It has the tendency of invading surrounding tissue and has the strong possibility of returning as a higher grade tumor.

Grade Four

A grade four tumor is the most aggressive type of brain tumor. It is made of abnormal cells that reproduce at a very high rate of speed. This tumor rapidly invades surrounding brain tissue and actually produces its own bloodflow so it can maintain its rapid pace.

As you can see, there are very distinct differences between the benign and malignant tumors. One of the things that should be noted about the malignant tumors is that they are usually shown as enhanced in MRIs when given a contrast injection. This means they take in the gadolinium very quickly and therefore appear brighter in the MRI.