Diagnosis and Grading

Some patients find out that they have a brain tumor only after undergoing an imaging scan for a different reason. Other patients learn about the tumor after experiencing severe symptoms such as seizures or debilitating new headaches.

However, even after physicians and radiologists have identified an abnormal mass in a patient’s brain, there are still many questions left to answer. They must identify whether the tumor is primary, or originating from the brain, or a metastasis coming from a cancer elsewhere in the body. They must determine whether the tumor is benign or malignant, and what type and grade it is. Answering these and other questions allows them to shape a patient’s treatment plan.

At Siteman Cancer Center, your condition will be assessed by specialized Washington University physicians as well as radiologists from the world-renowned Mallinckrodt Institute of Radiology. They will ensure that you get an accurate diagnosis and quickly start you on the path to treatment.

Many patients travel great distances to be seen at Siteman, so we try to make your time with us as efficient as possible. You may be scheduled for multiple tests and appointments on the same day to spare you from having to make additional trips to our facility.

How are brain tumors diagnosed?

In some cases, patients with brain tumors experience alarming symptoms that cause them to seek treatment in the emergency room. If you are not suffering from urgent or dangerous symptoms but still worry you may have a brain tumor, you should make an appointment with your primary care provider.

At your appointment, your doctor will talk with you about your concerns as well as your personal medical history and family history. He or she will then examine you, conducting a special exam to assess your neurological function. This exam is painless and mostly involves following a sequence of commands from your physician.

If your physician believes there is reason for concern, he or she will refer you for an imaging procedure, typically an MRI or CT scan. These are machines that use a magnetic field or X-rays to take pictures of the inside of the head and body.

At this point, if you are found to have a tumor, your care team will try to determine what type of tumor it is. In some cases, it will be straightforward to identify the tumor type based on your symptoms and imaging alone. In other cases, your physicians may not be able to fully identify the tumor until after it is removed, and they can perform tests on the tissue.

Sometimes, physicians are able to biopsy tumor tissue without performing an open surgery; this is called a stereotactic needle biopsy. They do this by drilling a small hole in the patient’s skull and extracting a tiny tissue sample with a needle. Patients are given anesthesia so they sleep during the procedure.

How are brain tumors graded?

Brain and spine tumors are assigned a “grade” that indicates their aggressiveness, ranging from I-IV. Grade I tumors are the least aggressive, and grade IV tumors are the most aggressive.

Certain tumor types are always associated with a particular grade. Glioblastoma, for instance, is always a grade IV tumor. In other cases, a tumor type can be one of several grades, which can be determined by pathological testing. For instance, an adult astrocytoma can be grade 2, 3, or 4. Finally, tumor grade may change over time. For instance, lower grade gliomas may progress to a higher grade.