Brain and spinal cord tumors in adults

What are brain and spinal cord tumors?
Tumors of the brain and spinal cord are masses of abnormal cells in the brain or spinal cord that have grown out of control.

In most other parts of the body, it is very important to distinguish between benign (non-cancerous) and malignant (cancerous). Benign tumors do not grow into nearby tissues or spread to distant areas, so in other parts of the body are almost never life threatening. One of the main reasons of malignant tumors are so dangerous is because they can spread throughout the body.

Although brain tumors rarely spread to other parts of the body, most of them can spread through the brain tissue. Even so-called benign tumors can, as they grow, press and destroy normal brain tissue, causing damage that often disabling and sometimes fatal. For this reason, doctors usually speak of "brain tumors" rather than "brain cancers." The main concerns with brain tumors and spinal cord are easily propagated through the rest of the brain or spinal cord and can be removed if not return.

Tumors of the brain and spinal cord tend to be different in adults and children. They often form in different areas, develop from different cell types, and may have a perspective and a different treatment.

This document refers only to brain tumors and spinal cord. Tumors in children are discussed in our document brain and spinal cord tumors in children.

The central nervous system

To understand the brain and spinal cord tumors, it helps to know about the normal structure and function of the central nervous system (CNS), which is the medical name for the brain and spinal cord.

The brain is the center of thought, feeling, memory, speech, vision, hearing, movement, and more. The spinal cord and special nerves in the head called cranial nerves help carry messages between the brain and the rest of the body. These messages tell our muscles how to move, transmit information gathered by our senses, and help coordinate the functions of our internal organs.

The brain is protected by the skull. Also, the spinal cord is protected by the bones (vertebrae) of the spine.

The brain and spinal cord are surrounded and cushioned by a special liquid, called cerebrospinal fluid (CSF). CSF is made by the choroid plexus, found in the spaces within the brain called ventricles. The ventricles and the spaces around the brain and spinal cord are filled with cerebrospinal fluid.

Parts of the brain and spinal cord



The main areas of the brain include the cerebrum, cerebellum and brain stem. Each of these parts has a special function.

Brain: The brain is the largest, outside of the brain. It has 2 hemisferios (halves) and controls reasoning, thought, emotion and language. It is also responsible for planned muscle movements (voluntary) (throw a ball, walking, chewing, etc.) and to take and interpret sensory information such as vision, hearing, smell, touch and pain.

The symptoms caused by a tumor in a cerebral hemisphere depend on the location of the tumor. Common symptoms include:

Seizures
Slurred speech
A change of mood such as depression
A change in personality
Weakness or paralysis on one side of the body
Changes in vision, hearing or other senses
Basal ganglia: The basal ganglia are structures deep within the brain that help control our muscle movements. Tumors or other problems in this part of the brain that normally cause weakness, but in rare cases can cause tremor or other involuntary movements.

Cerebellum: The cerebellum is located below the brain at the back of the brain. It helps to coordinate movement. Cerebellar tumors can cause problems with coordination in walking, difficulty with the precise movements of the hands, arms, feet and legs, trouble swallowing or timing of eye movements, and changes in rhythm of speech.

Brainstem: The brainstem is the lower part of the brain that is connected to the spinal cord. It contains bundles of very long nerve fibers that carry signals controlling muscles and sensation or feeling between the brain and the rest of the body. Special centers in the brain stem also help control breathing and heartbeat. In addition, most cranial nerves (which carry signals directly between the brain and face, eyes, tongue, mouth and other areas) start in the brain stem.

Tumors in this critical area of ​​the brain may cause weakness, muscle stiffness, or problems with sensation, facial movement or eye, ear, or swallowing. Double vision is a common early symptom of brain stem tumors, as are problems with coordination in walking. Because the brain stem is a small area that is so essential for life, it may not be possible to surgically remove tumors in this area.

Spinal cord: The spinal cord has bundles of very long nerve fibers that carry signals controlling muscles, sensation or feeling, and bladder and bowel control.

Tumors of the spinal cord can cause weakness, paralysis or numbness. The spinal cord is a narrow structure, so within tumors usually cause symptoms on both sides of the body (for example, weakness or numbness in the legs). This is different from most brain tumors, which often affect one side of the body.

The nerves supplying arms start in the spinal cord in the neck (cervical spine). The nerves that branch out from the spinal cord of the legs, bowel and bladder are presented in the back (thoracic and lumbar spine). Most spinal cord tumors begin in the neck (cervical spine) and can cause symptoms in the arms and legs, as well as affect the function of the bowel and bladder. Tumors of the spinal cord below the neck only affect the legs and bowel and bladder function



Cranial nerves Cranial nerves extend directly from the base of the brain (as opposed to leaving the spinal cord). Tumors starting in cranial nerves may cause vision problems, difficulty swallowing, loss of hearing in one or both ears, or facial paralysis, numbness or pain.

Types of cells and tissues in the brain and spinal cord

The brain and spinal cord are many types of tissues and cells that can develop into different types of tumors.

The neurons (nerve cells): These are the most important cells in the brain. Transmit chemical and electrical signals that determine thought, memory, emotion, speech, muscle movement, sensation, and almost everything else that the brain and spinal cord do. Neurons send these signals through their nerve fibers (axons). The axons in the brain tend to be short, while the spinal cord can be as long as several feet.

Unlike many other types of cells that can grow and divide to repair damage caused by injury or disease, neurons in the brain and spinal cord largely stop dividing about a year after birth (with some exceptions). Neurons do not usually form tumors, but they are often damaged by tumors that start nearby.

Glial cells: Glial cells are supporting cells of the brain. Most brain tumors and spinal cord develop from glial cells. These tumors are sometimes referred to as gliomas.

There are 3 types of glial cells - astrocytes, oligodendrocytes, and ependymal cells. A fourth cell type called microglia is part of the immune system and is not really a glial cell.

Astrocytes help support and nourish neurons. When the brain is injured, astrocytes form scar tissue that helps repair the damage. Main tumors from these cells are called astrocytomas or glioblastomas.
Oligodendrocytes make myelin, a fatty substance that surrounds and insulates the axons of nerve cells in the brain and spinal cord. This helps neurons send electrical signals through axons. Tumors starting in these cells are called oligodendrogliomas.
Ependymal cells lining the ventricles (fluid-filled areas) in the central part of the brain and the shape of the channel through which flows the LCR. Tumors that begin in these cells are called ependymomas.
Microglia are the immune cells (fight infection) CNS.
Neuroectodermal cells: They are very early forms of nervous system cells, which are probably involved in the development of brain cells. They are found throughout the brain, but often are not seen in the adult central nervous system. The most common tumors arising from these cells develop in the cerebellum and are called medulloblastomas.

Meninges: These are layers of tissue that cover and protect the brain and spinal cord. CSF travels through the spaces formed by the meninges. The most common tumors that start in these tissues are called meningiomas.

Choroid plexus: The choroid plexus is the area of ​​the brain within the ventricles that makes CSF, which nourishes and protects the brain.

The pituitary gland and the hypothalamus: The pituitary gland is a small gland at the base of the brain. It is connected to a part of the brain called the hypothalamus. Both produce hormones that help regulate the activity of several other glands in the body. For example, control the amount of thyroid hormone produced by the thyroid gland, the production and release of milk from the breasts, and the number of male or female hormones made by the testicles or ovaries. They also make growth hormone, which stimulates body growth, and vasopressin, which regulates water balance by the kidneys.

The growth of tumors in or near the pituitary or hypothalamus and surgery and / or radiotherapy in this area, may affect these functions. For example, tumors that begin in the pituitary gland sometimes make too much of a certain hormone, which can cause problems. On the other hand, a person may have low levels of one or more hormones after treatment and may need to take hormones to compensate for this.

Pineal gland: The pineal gland is not really part of the brain. It is, in fact, a small endocrine gland located between the cerebral hemispheres. It makes melatonin, a hormone that regulates sleep, in response to changes in light. The most common tumors of the pineal gland are called pineoblastomas.

Blood-brain barrier: The lining of the small blood vessels (capillaries) in the brain and spinal cord create a very selective barrier between the blood and tissues of the central nervous system. This barrier normally helps maintain the metabolic balance of the brain and keeps harmful toxins from entering the brain. Unfortunately, it also keeps out most chemotherapy drugs used to kill cancer cells, which in some cases limits their usefulness.