Staging

Staging is a way of describing a tumor, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the tumor's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of tumors.

There is no formal staging system for childhood brain stem glioma. A tumor may be classified as either diffuse or focal. In addition, the tumor may be classified by its grade, which is a measure of how much the tumor cells appear like normal cells. Low-grade tumors are less aggressive than high-grade tumors.

Diffuse brain stem glioma. This type of tumor spreads freely throughout the pons and often spreads to the midbrain, the medulla, or nearby parts of the brain. These tend to be high-grade tumors; they are very aggressive and contain abnormal-looking cells.

Focal brain stem glioma. About 20% of brain stem tumors are focal, meaning they occur at one point or are contained within a small segment of the brain stem. They usually occur in the midbrain or medulla, rather than the pons. These are usually benign or low-grade tumors; they are less aggressive and the tumor cells look fairly normal.

Recurrent brain stem glioma: Recurrent brain stem glioma is a tumor that comes back after treatment.