What Is the Most Common Type of Brain Tumor?

Other common types of brain tumors include:

• Gliomas: Tumors that begin in the supporting tissue of the brain or spinal cord. Subtypes include:
  • Astrocytomas
  • Ependymomas
  • Glioblastomas
  • Oligoastrocytomas
  • Oligodendrogliomas
• Acoustic neuromas (schwannomas): Noncancerous tumors that develop on the auditory nerves, which control balance and hearing and lead from your inner ear to your brain. If the tumor presses on the nerve, you may face balance and hearing issues.
• Pituitary adenomas: Tumors that originate from the pituitary gland, which is a small endocrine organ located at the base of the brain. If they grow, they can press on the nerve that controls your eyesight and cause vision problems. Sometimes, they can release more quantities of pituitary hormones, which can affect the functioning of multiple systems in the body. This can lead to hyperprolactinemia, hypothyroidism, diabetes insipidus, etc.
• Medulloblastomas: Cancerous tumors that start in the lower back part of the brain. Although they are most common in children, they can occur at any age.

You cannot determine whether a tumor is benign or malignant from symptoms alone. While your doctor may be able to tell you the nature of your tumor from an MRI scan, that is not always possible—imaging tests do not provide a confirmatory diagnosis.

In most cases, a biopsy is required. A biopsy involves the surgical removal of a small piece of the brain that is sent to a lab for analysis under a microscope.

Primary brain tumors are those that originate from the brain or tissues close to the brain. Tumors arising from the meninges, cranial nerves, pituitary gland, or pineal gland are also called primary brain tumors.

Metastatic brain tumors are also known as secondary brain cancer. They are cancerous cells or tumors that are formed in other organs of the body and have spread to the brain. The two most common types of cancer that cause metastatic brain tumors are lung cancer and breast cancer, followed by kidney cancer, colon cancer, and skin cancer (melanoma).

In adults, metastatic brain tumors are much more common than primary brain tumors. They often occur in people who have had cancer in the past.

Signs and symptoms of a brain tumor depend on 3 factors:

• Size
• Location
• Rate of growth

Symptoms vary greatly and may include:

• New-onset headache or frequent headaches that are of a different nature
• Nausea or vomiting (with no other cause)
• Vision problems:
  • Blurred vision
  • Double vision
  • Loss of peripheral vision
• Speech difficulties
• Hearing problems
• Seizures
• Decreased ability to move an arm or a leg
• Decreased sensation in an arm or leg
• Difficulty maintaining balance
• Fatigue
• Confusion
• Problems with decision-making 
• Personality or behavior changes

Doctors have not yet found a clear cause of primary brain tumors, but factors that may increase your risk include:

• Exposure to radiation (such as radiation therapy used to treat cancer and radiation exposure caused by atomic bombs)
• Family history of brain tumors

Brain tumors can cause symptoms similar to those found in other, less serious conditions. Your doctor will first try to rule out other causes before arriving at a diagnosis. They will ask about related symptoms, take your medical history, and conduct a neurological examination.

A neurological examination checks your vision, hearing, balance, coordination, strength, and reflexes. This may help your doctor determine the location of the brain tumor.

Diagnostic tests include:

• Imaging tests: Your doctor will most likely order MRI scans. A dye may be injected into your veins for a contrast MRI, enhancing the images of the brain, tumor, and blood supply to the affected area. Sometimes, your doctor may ask you to undergo other imaging tests such as CT and PET scans. A CT scan is often required to determine the surgical approach, and a PET scan helps the doctor determine whether there is cancer in other organs of the body.
• Biopsy: A biopsy can be done either through a stereotactic needle biopsy or during surgery to remove the brain tumor. A stereotactic needle biopsy involves drilling a small hole in your brain and using a thin needle to remove a small tissue of the brain. MRI or CT scans are most often used during the procedure to guide the insertion of the needle and removal of the piece of the tumor. This approach is used for tumors that are hard to reach and those located in sensitive areas of the brain.