Diagnosis of Brain Tumor

Types of Primary Brain Tumors

There are many types of primary brain tumors. Primary brain tumors are named according to the type of cells or the part of the brain in which they begin. For example, most primary brain tumors begin in glial cells. This type of tumor is called a glioma. Among adults, the most common types are: Astrocytoma: The tumor arises from star-shaped glial cells called astrocytes. It can be any grade. In adults, an astrocytoma most often arises in the cerebrum.
  • Grade I or II astrocytoma: It may be called a low-grade glioma.
  • Grade III astrocytoma: It’s sometimes called a high-grade or an anaplastic astrocytoma.
  • Grade IV astrocytoma: It may be called a glioblastoma or malignant astrocytic glioma.
Meningioma: The tumor arises in the meninges. It can be grade I, II, or III. It’s usually benign (grade I) and grows slowly. Oligodendroglioma: The tumor arises from cells that make the fatty substance that covers and protects nerves. It usually occurs in the cerebrum. It’s most common in middle-aged adults. It can be grade II or III. Among children, the most common types are: Medulloblastoma: The tumor usually arises in the cerebellum. It’s sometimes called a primitive neuroectodermal tumor. It is grade IV. Grade I or II astrocytoma: In children, this low-grade tumor occurs anywhere in the brain. The most common astrocytoma among children is juvenile pilocytic astrocytoma. It’s grade I. Ependymoma: The tumor arises from cells that line the ventricles or the central canal of the spinal cord. It’s most commonly found in children and young adults. It can be grade I, II, or III. Brain stem glioma: The tumor occurs in the lowest part of the brain. It can be a low-grade or high-grade tumor. The most common type is diffuse intrinsic pontine glioma.

Risk Factors

A risk factor is something that may increase the chance of getting a disease. Studies have found the following risk factors for brain tumors:
  • Ionizing radiation: Ionizing radiation from high dose x-rays (such as radiation therapy from a large machine aimed at the head) and other sources can cause cell damage that leads to a tumor. People exposed to ionizing radiation may have an increased risk of a brain tumor, such as meningioma or glioma.
  • Family history: It is rare for brain tumors to run in a family. Only a very small number of families have several members with brain tumors.

Symptoms

The symptoms of a brain tumor depend on tumor size, type, and location. These are the most common symptoms of brain tumors:
  • Headaches (usually worse in the morning)
  • Nausea and vomiting
  • Changes in speech, vision, or hearing
  • Problems balancing or walking
  • Changes in mood, personality, or ability to concentrate
  • Problems with memory
  • Muscle jerking or twitching (seizures or convulsions)
  • Numbness or tingling in the arms or legs

Diagnosis of Brain Tumor

If you have symptoms that suggest a brain tumor, you may have one or more of the following tests:
  • Neurologic exam: Your doctor checks your vision, hearing, alertness, muscle strength, coordination, and reflexes. Your doctor also examines your eyes to look for swelling caused by a tumor pressing on the nerve that connects the eye and the brain.
  • MRI: A large machine with a strong magnet linked to a computer is used to make detailed pictures of areas inside your head. Sometimes a special dye (contrast material) is injected into a blood vessel in your arm or hand to help show differences in the tissues of the brain. The pictures can show abnormal areas, such as a tumor.
  • CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of your head. You may receive contrast material by injection into a blood vessel in your arm or hand. The contrast material makes abnormal areas easier to see.
  • Angiogram: Dye injected into the bloodstream makes blood vessels in the brain show up on an x-ray. If a tumor is present, the x-ray may show the tumor or blood vessels that are feeding into the tumor.
  • Spinal tap: Your doctor may remove a sample of cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). This procedure is performed with local anesthesia. The doctor uses a long, thin needle to remove fluid from the lower part of the spinal column. A spinal tap takes about 30 minutes.
  • Biopsy: The removal of tissue to look for tumor cells is called a biopsy. A pathologist looks at the cells under a microscope to check for abnormal cells. A biopsy can show cancer, tissue changes that may lead to cancer, and other conditions. A biopsy is the only sure way to diagnose a brain tumor, learn what grade it is, and plan treatment. Surgeons can obtain tissue to look for tumor cells in two ways:
    • Biopsy at the same time as treatment: The surgeon takes a tissue sample when you have surgery to remove part or the entire tumor.
    • Stereotactic biopsy: You may get local or general anesthesia and wear a rigid head frame for this procedure. The surgeon makes a small incision in the scalp and drills a small hole (a burr hole) into the skull. CT or MRI is used to guide the needle through the burr hole to the location of the tumor. The surgeon withdraws a sample of tissue with the needle. A needle biopsy may be used when a tumor is deep inside the brain or in a part of the brain that can’t be operated on.
Learn more: Treatment Options for Brain Tumors If you have symptoms associated with a brain tumor, contact us to request an appointment with our oncology specialists to to begin diagnostic testing or to obtain a second opinion.