Nearly 80,000 people, including adults and children, are expected to be diagnosed with primary brain tumor in the United States this year. Read information specific to pediatric brain tumors.
A brain tumor is an abnormal growth of tissue in the brain. The most common surgical treatments are removal via craniotomy or transsphenoidal surgery. Other common surgical treatments include radiosurgery and laser interstitial ablation therapy. In some cases, a tumor may not be amenable to surgical removal, but a surgical biopsy may still be necessary to definitively diagnose the tumor before proceeding with medical treatments.
Depending on a brain tumor’s origin, it is classified as either primary or secondary, and depending on a brain tumor’s behavior, it is classified as either benign or malignant.
A benign tumor does not contain cancer cells and usually, once removed, does not recur. Most benign brain tumors do not invade surrounding tissue and therefore have clear borders; however, these tumors can cause symptoms similar to malignant tumors because of their size and location in the brain. Often, benign tumors can be cured with resection.
Malignant brain tumors contain cancer cells, are usually fast growing and invade surrounding tissue. Malignant brain tumors very rarely metastasize outside of the brain, but they often spread beyond the margins of the resection and thus, may recur after treatment.
The World Health Organization grades tumors on a scale of one to four on the basis of tumor cell appearance and tumor behavior. The higher the grade, the more aggressive and abnormal the tumor.
- Grade 1 tumors are slow growing and benign, and they do not spread in the brain.
- Grade 2 tumors are slow growing but the cells have an abnormal appearance and can progress to higher grades over time.
- Grade 3 tumors are fast growing and malignant.
- Grade 4, the most malignant and aggressive tumors, are fast growing with highly abnormal cellular appearance.
There are also some molecular features that have great influence on prognosis for brain tumors, the most important of which is the mutation of a gene called IDH1.
There are many different types of brain tumors, and they are usually categorized by the type of cell from which the tumor originates. Some tumors are also categorized by the area of the brain where they occur. The most common types of brain tumors include the following:
Gliomas, the most common type of primary brain tumor, begin from glial cells. There are several types of gliomas, categorized by where they are found and the type of cells that started the tumor. For information about gliomas, please click here. The following are the different types of gliomas:
- Astrocytomas are a common type of glioma, and they can be found anywhere in the brain or spinal cord. For information about astrocytomas, please click here. (Astrocytomas in the spine are handled by the specialists at our Spine Hospital.)
- Oligodendrogliomas, which make up about 10 to 15 percent of gliomas, are found commonly in the cerebrum.
- Ependymomas, which are rare and develop mostly in children, arise from ependymocytes.
- Mixed gliomas contain more than one type of glial cell. Mixed gliomas make up about 5 to 10 percent of gliomas.
- Gangliogliomas develop from both glial cells and nerve cells and are rare.
- Optic nerve gliomas develop on the astrocytes around the optic nerves, which transmit visual information from the retina at the back of each eye to the brain.
- Brain stem gliomas are tumors found in the brainstem and occur almost exclusively in children.
- Cerebellar astrocytoma are tumors that develop in the cerebellum.
Meningiomas are usually benign, slow-growing tumors that originate from the meninges and may exist for years before being detected.
Schwannomas are benign nerve sheath tumors that arise from Schwann cells and are most commonly found on the eighth cranial nerve, which controls hearing and balance. Schwannomas in this location are sometimes also called vestibular schwannomas or acoustic neuromas.
Primitive neuroectodermal tumors
Primitive neuroectodermal tumors (PNETs) are found in the cerebrum, and when observed under a microscope, they are identical to medulloblastomas. Medulloblastomas differ in the location in which they are found. PNETs are fast-growing and often malignant, with occasional spreading throughout the brain or spinal cord.
Medulloblastomas are malignant tumors found near the midline of the cerebellum and can metastasize to other areas of the central nervous system, especially around the spinal cord.
Craniopharyngiomas are benign, slow-growing tumors that occur at the base of the brain near or in the pituitary.
Pineal region tumors
Many different tumors can arise near the pineal gland, including gliomas, meningiomas, germ cell tumors, pineal cell tumors, and pineal cysts.
Clival tumors are growths on the base of the skull, specifically the clivus, and are classified as either a chordoma or a chondrosarcoma.
Esthesioneuroblastomas, an extremely rare tumor that develops in the nose, arises from olfactory nerve cells.
The most common brain tumors among adults are secondary brain tumors, also called metastatic brain tumors. These are tumors that begin to grow in another part of the body, then metastasize to the brain through the bloodstream. When the tumors metastasize to the brain, they commonly go to the cerebrum and sometimes to the cerebellum. Often, an individual may have multiple metastatic tumors in several different areas of the brain. Common types of cancer that can travel to the brain include lung cancer, breast cancer, melanoma, and colon cancer, all of which are considered malignant once they have spread to the brain.
The following are the most common symptoms of a brain tumor; however, each person may experience symptoms differently. Symptoms vary depending on the size and location of tumor, and many symptoms are related to an increase in pressure in or around the brain because there is no spare space in the skull for anything except the delicate tissues of the brain and its fluid. Any tumor, extra tissue, or fluid can cause pressure on the brain and lead to increased intracranial pressure. In particular, increased intracranial pressure can be caused by a tumor blocking one or more of the ventricles that drain cerebrospinal fluid, leading to hydrocephalus.
Increased intracranial pressure may lead to headache, vomiting, nausea, personality changes, irritability, drowsiness, depression, and decreased cardiac and respiratory function, which can eventually lead to coma if not treated.
One of the most common symptoms of brain tumors is headache, but the majority of headaches are not caused by brain tumors. Headaches caused by brain tumors tend to worsen when lying down or upon first waking; they tend to recur, eventually becoming constant.
Symptoms are usually specific to where a brain tumor is located and its size.
Symptoms of brain tumors in the cerebrum may include:
- Increased intracranial pressure
- Visual changes, such as vision loss
- Slurred speech
- Loss of ability to write
- Impaired sense of smell
- Personality changes
- Impaired judgment
- Difficulty remembering and memory loss
- Hemiparesis or hemiplegia
- Gait disturbances
Symptoms of brain tumors in the brainstem may include:
- Increased intracranial pressure
- Endocrine problems
- Visual changes or diplopia
- Hemiparesis or hemiplegia
- Respiratory changes
- Clumsy, uncoordinated gait
- Hearing loss
- Personality changes
Symptoms of brain tumors in the cerebellum may include:
- Increased intracranial pressure
- Uncoordinated muscle movements
The symptoms of a brain tumor may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
In addition to a complete medical history and physical examination, a neurological examination is usually conducted to identify symptoms and any problems. This exam consists of evaluating eye movements, hearing, sensation, motor function, swallowing, sense of smell, balance, and coordination.
The primary component of diagnosing brain tumors is imaging studies. The preferred imaging test is most often a magnetic resonance imaging (MRI) scan because it provides superior tumor detail, but a computed tomography (CT) scan is a good alternative. MRI or CT scans may be performed with or without contrast enhancement.
Depending on the suspected tumor type, additional procedures may be performed that include:
- A cerebral angiogram, a minimally invasive procedure, can be performed to image the blood vessels in the tumor, particularly for highly vascular tumors.
- An X-ray of the chest may be performed to identify where in the body the tumor started before it metastasized to the brain.
- A bone scan can be used to detect tumors and bone abnormalities.
- A myelogram may be done to detect tumor metastasis.
- Spinal tap, a procedure in which a special needle is placed into the spinal canal, may be done to obtain a small amount of cerebrospinal fluid for testing to identify cancer cells or determine if there is an infection or other problems.
- A blood draw may be done to check for tumor markers that indicate a particular tumor type.
- Positron emission tomography (PET) scan, which involves injecting radioactive glucose so that it can be traced in the body, can be used to detect malignant tumor cells, which are more active and therefore take up more glucose than normal cells do.
- Magnetic resonance spectroscopy (MRS) is a procedure that detects the chemical composition of the tumor as a means to identifying the tumor type.
To confirm a diagnosis, a biopsy is typically performed before or during surgery.
The exact cause of most brain tumors is unclear.
For many tumors, genetic mutations or chromosomal abnormalities are known to be associated with tumor occurence.
Most brain tumors are sporadic, but some are linked to certain genetic conditions, such as neurofibromatosis type I and II, von Hippel-Lindau disease, Li-Fraumeni syndrome, Turcot syndrome, tuberous sclerosis, and nevoid basal cell carcinoma syndrome.
Individuals who have received radiation therapy to the head as part of prior treatment for other malignancies have an increased risk for new brain tumors.
Brain tumors can occur at any age but are most common during early or middle adulthood. Both men and women can have brain tumors but men have a slightly higher risk.
At Columbia, our neurosurgeons use the latest surgical techniques to successfully treat brain tumors, providing the best possible outcome for each patient. Specific treatment for brain tumors depends on several factors, such as type, location, and size of the tumor in addition to an individual’s age, overall health, and medical history.
For most brain tumors, the first step of treatment is usually surgery, the goal of which is to remove as much of the tumor as possible while maintaining neurological function. If complete resection is achieved, the tumor may be cured; however, for some tumors, only subtotal resection is possible because otherwise normal brain tissue could risk damage. Our highly skilled neurosurgeons are careful to excise as much tumor as possible while preserving brain tissue and overall function.
Brain tumor surgery can be performed by craniotomy or transsphenoidal surgery to remove the tumor, depending on what is best for the patient and tumor type. If hydrocephalus is present, a ventriculoperitoneal shunt will need to be surgically placed into the blocked ventricle before or during surgery. The other end of the tube is placed into the abdomen to help drain excess fluid that can otherwise build up in the brain and cause an increase in pressure inside the skull.
If residual tumor remains, adjuvant therapy along with radiation therapy, chemotherapy, or both may be needed.
One of the newer therapies that may be used to treat brain cancer is stereotactic radiosurgery. This technique focuses high doses of radiation at the tumor site, while sparing the surrounding normal tissue, with the use of photon beams from a linear accelerator or cobalt X-rays.