Having the correct diagnosis is critical to deciding the best treatment approach for a brain tumor. There are more than 125 types of brain tumors. Because pathologists, radiologists, and other members of the Brain Tumor Center focus only on brain tumors, our doctors bring a high level of expertise to diagnosis and treatment planning.

We diagnose brain tumors through a multistep process that considers your symptoms, your medical history, a neurological examination, and other tests. A multidisciplinary team of brain tumor specialists weighs a number of factors in deciding on treatment options for you, including the size and location of the tumor(s), the grade (aggressiveness) of the cancer, and your overall health.

Diagnostic Imaging

If your symptoms and the result of a neurological examination indicate that you might have a brain tumor, your doctors may recommend diagnostic imaging. A variety of noninvasive tools can look inside the brain to identify the presence of a brain tumor, as well as its size, location, and extent. Techniques used at the Brain Tumor Center include MRI, CT, and PET scans.

Knowing the size and location of the tumor helps neurosurgeons plan the best approach to performing a biopsy or surgery to remove the tumor.


If diagnostic imaging reveals a tumor in the brain, the only way to determine its type and whether it is cancerous is to perform a biopsy of the tissue. The location of the tumor dictates how this procedure is performed, which may be part of a larger operation to actually remove the tumor.

Once the tissue is removed, it is sent to a pathologist who specializes in analyzing brain tumors. By looking closely at the sample, a pathologist can determine what type of tumor it is and other information that is important in planning your treatment.

In many cases, surgery is necessary to remove all or most of the tumor. During a craniotomy, a procedure performed by removing skull bone, tissue is sent to the pathologist for examination under a microscope.

When a tumor lies deep in the brain or in a critical area, another option is to perform a needle biopsy. Using a three-dimensional imaging device to guide the procedure, the neurosurgeon navigates a very thin needle to the exact location of the tumor and removes a sample of the tissue, without disturbing the normal brain tissue.

In this minimally invasive procedure, a neurosurgeon uses an endoscope—a thin, tube-like instrument with a light and a lens on its tip—to operate through a small opening in the skull.

In rare cases, a doctor may also perform a lumbar puncture, also known as a spinal tap, to remove a sample of spinal fluid to look for abnormal cells that might help to detect a tumor.

New Diagnostic Strategies

Brain Tumor Center researchers are striving to better understand a protein tumor marker known as YKL-40, which has been found in higher than usual amounts in the blood of patients with glioblastoma, the most common type of brain tumor. Being able to track a tumor marker in patients with brain tumors could help with diagnosis and during treatment, enabling doctors to monitor the effectiveness of therapy and identify a potential recurrence of cancer after treatment.

Memorial Sloan Kettering’s neuro-oncology molecular imaging program is also researching the specific molecular abnormalities that characterize malignant brain tumors and ways in which PET scans can be used to help monitor the effects of therapy.

Personalized Medicine

The Brain Tumor Center is one of just a few centers in the world that has begun to use personalized, molecular medicine as a routine part of the treatment of brain tumors. This new approach to medicine considers genetic information from your tumor to determine which treatments are most likely to be effective.

Memorial Sloan Kettering pathologists analyze the DNA within the tumor cells in a biopsy sample and look for specific mutations that are associated with particular subtypes of brain tumors. This information can indicate which types of chemotherapy are more likely than others to shrink or control the tumor, and can guide your doctors’ decision making.

The Brain Tumor Center also stores all tissue taken from patients in a tissue bank. Preserving the brain tumor tissue gives us the ability to analyze it at a later point in your care — without the need for an additional biopsy — if the current treatment is not improving your condition. Information from the molecular profiling of your tissue can also help your doctors to determine which clinical trials would be most relevant for you.

In addition, researchers at the Brain Tumor Center are studying brain tumor tissue samples to better understand the biology of different subtypes of brain tumors. Our hope is that these samples contain information that will enable us to continue to improve treatment.