Most people with CNS symptoms first go to the emergency department, as symptoms can come on suddenly. From the emergency department, they are usually admitted to the hospital, where they’re evaluated by a neurosurgeon. The neurosurgeon will determine next steps, such as a scan, a biopsy (procedure to remove a sample of tissue) or resection (surgery to remove a larger portion of the affected tissue). From there, the neurosurgeon will make a diagnosis based on a pathology report of the biopsy or resection.

Neurological (CNS) Cancer Diagnosis

To make a diagnosis, your doctor will run tests to determine if you have cancer. Tests may include: 

  • Health history and physical exam: Your physician will check your overall physical health, particularly looking for signs of disease. They’ll also review your past illnesses, treatments and health habits.
  • Neurological exam: This is an exam to check your mental status, ability to walk, coordination and how well your senses, reflexes and muscles function.
  • Visual field exam: This test measures your central vision (what you can see when looking straight ahead) and peripheral vision (what you can see in other directions when looking straight ahead). Vision loss can be a sign that a tumor is affecting the part of the brain that controls eyesight.
  • Tumor marker test: A test in which a sample of tissue, blood or urine is measured for certain substances (called tumor markers) linked to specific types of cancer.
  • Gene testing: A test in which cells or tissues are studied to look for gene or chromosome changes. These changes can signal that a person is at increased risk of developing a certain type of disease, like cancer.
  • Computed tomography (CT) scan: A CT scan (also called a CAT scan) takes X-rays of the body from different angles to create a three-dimensional image that shows tumors or abnormalities. Sometimes ink or dye is swallowed or injected into the vein, so tissues and organs show up clearly on the scan.
  • Positron emission tomography (PET) scan: During a PET scan, a small amount of a radioactive sugar substance is injected into the body. Cells that use the most energy, such as cancer cells, absorb more of this substance than other cells. Then, a scanner creates images of your organs and tissues. Sometimes PET and CT scans are done together.
  • Magnetic resonance imaging (MRI): This test uses magnetic fields instead of X-rays to create images of the inside of the body, such as the neck, head, chest and lymph nodes. An MRI can also help your doctor measure the size of the tumor.
  • Single-photon emission computed tomography (SPECT) scan: A procedure in which a small amount of a radioactive substance is inhaled through the nose or injected into a vein. As the substance travels through the body, the scanner takes pictures of the brain. These images can show areas of increased blood flow and activity in the body, which may indicate the growth of cancer cells.
  • Biopsy: If imaging tests indicate that you may have a brain tumor, your physician may recommend a biopsy. During a biopsy, a small sample of tissue is removed from the affected area of the body. This tissue is examined under a microscope for signs of cancer. A biopsy is the only way to make an official cancer diagnosis. There are two types of biopsies used to diagnose brain tumors:
    • Stereotactic biopsy: A procedure that uses a 3-dimensional scanning device and computer to detect the tumor. During the procedure, a biopsy needle is inserted through a small hole in the skull. The needle removes some cells or tissue, which can then be studied under a microscope by a pathologist to look for signs of cancer.
    • Open biopsy: During an open biopsy, a portion of the skull is removed (also called a craniotomy). The surgeon will remove a portion of brain tissue, which a pathologist will then study under a microscope for signs of cancer. If the pathologist detects signs of cancer, the surgeon will then remove some or all of the tumor during the same surgery with the least amount of damage to normal brain tissue.

Once a pathologist has a biopsy sample, they can use the following tests to determine the type and grade of the tumor: 

  • Immunohistochemistry: A lab test that uses antibodies to check for specific markers called antigens in the tissue. This test can help distinguish between different types of neurological (CNS) tumors.
  • Light and electron microscopy: A test that looks for changes in the cells using regular and high-powered microscopes.
  • Cytogenetic analysis: A test that examines brain tissue samples for missing, extra, rearranged or broken chromosomes. Chromosomal changes can sometimes be a sign of cancer. A cytogenetic analysis may also be used to help plan treatment and determine how well treatment is working.


In some cases, a biopsy or surgery isn’t safe or possible. If this is the case, your physician will use imaging tests and other procedures to make a diagnosis.

Chance of Recovery from Neurological (CNS) Cancer

The prognosis, or chance of recovery, from primary spinal cord and brain tumors depends on the following factors:

  • The type and grade of tumor
  • Where the tumor is located
  • Whether the tumor can be surgically removed
  • Whether you have chromosomal changes
  • Whether the tumor has been recently diagnosed or has come back after previous treatment
  • Your overall health

Neurological (CNS) Cancer Grading 

Physicians use grading (rather than staging) to diagnose brain and spinal cord tumors. The grade of the tumor describes:

  • Whether it’s slow-growing or fast-growing
  • How abnormal the tumor cells look under a microscope
  • How likely the tumor is to spread elsewhere in the body

WHO Tumor Grading System

The World Health Organization (WHO) grades tumors as follows:

  • Grade I (low-grade): The tumor cells resemble normal cells under a microscope. These tumors tend to grow more slowly than other tumor grades and rarely spread elsewhere. Grade I tumors can sometimes be completely removed during surgery.
  • Grade II: The tumor cells grow and spread more slowly than in higher grades, but they may still spread to nearby tissue or come back after treatment. Sometimes, grade II tumors can become grade III or IV tumors.
  • Grade III: The tumor cells look abnormal under a microscope. Grade III tumors tend to grow quickly and spread to nearby tissue.
  • Grade IV: The tumor cells don’t resemble normal cells under a microscope. They grow and spread rapidly. The tumor may also contain dead cells. Grade IV tumors can rarely be completely removed by surgery.