Low-Grade Glioma Diagnosis


Getting an accurate diagnosis is a very important first step with low-grade glioma, so we can treat the condition right away. At Memorial Sloan Kettering, we’ll examine you and make a diagnosis based on a number of different factors, including:

  • the signs and symptoms you’re experiencing
  • your medical history and the condition of your health overall
  • the results of your neurological examination and other tests
  • the size, location, and grade (aggressiveness) of the tumor based on diagnostic imaging tests

Diagnostic Imaging

If your doctors suspect that you have a low-grade glioma, they may recommend diagnostic imaging to learn more about what’s going on. Our Brain Tumor Center specialists use CT, PET scans, and MRI to identify a tumor in the brain.

We can use results from these tests to figure out the size, location, and grade of the tumor. This information also helps our surgeons plan the best approach for a biopsy and surgery if needed.

Biopsy of Low-Grade Glioma

A biopsy is a very important part of diagnosing low-grade glioma. Because these types of tumors are difficult to reach, we usually get biopsy samples at the same time we do the surgery to remove the tumor. An exception to this might be if your tumor is very deep in your brain or in an extremely sensitive area. In this case it may be safer for us to remove a smaller sample of tissue rather than do extensive surgery.

An appointment to see a neurologist or neurosurgeon at the Brain Tumor Center is usually available within days. Learn More »

To do a biopsy, a surgeon removes a sample of tissue from the affected area and sends it to a pathologist to analyze under a microscope. The pathologist determines what type of tumor it is and provides any other information that can help your treatment team customize the most effective plan of care for you.

The location of the tumor in your head helps us plan which approach to use. Common biopsy approaches for low-grade glioma include:


In this procedure, the surgeon removes a piece of your skull bone to access the tumor and removes a sample of the tissue for a pathologist to analyze.

Needle Biopsy

Tumors located deep in your brain may require a fine needle aspiration biopsy. For this procedure, MSK surgeons use 3-D imaging to guide a very thin needle into the tumor and remove a tissue sample. This approach helps protect healthy brain tissue.


In this procedure, the surgeon uses a thin tube with a light and lens on its tip called an endoscope to operate through a small opening in the skull and get tissue for a pathologist to analyze.

Lumbar Puncture (Spinal Tap)

With a spinal tap, the surgeon removes a sample of the fluid around your spine. Finding abnormal cells in this fluid may indicate the presence of a tumor.