Brain and spinal cord tumors in children

What are brain and spinal cord tumors in children?
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 invade nearby tissue or spread to distant areas, so in other parts of the body are almost never life threatening. One of the main reasons malignant tumors (cancers) 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 and spinal cord tissue. Even so-called benign tumors can, as they grow, press and destroy normal brain tissue, causing damage that often disabling and can sometimes cause death. That is why doctors usually speak of "brain tumors" rather than "brain cancers." The main concerns with brain tumors and spinal cord are how fast they grow, how easily spread through the rest of the brain or spinal cord, and if it can be removed or treated and did not return. But both benign and malignant tumors can be life threatening.

Brain and spinal cord tumors in children tend to be different from those of adults. Often they form in different places, develop from different cell types, and may have a different treatment and prognosis (outlook). This document only refers to the brain and spinal cord tumors in children. Tumors in adults are discussed in our brain tumors document and adult spinal cord.

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 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 fluid called cerebrospinal fluid (CSF). CSF is made by the choroid plexus, found in the spaces in 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 area has a special function.

Brain: The brain is the largest, outside of the brain. It consists of two hemisferios (halves) and reasoning, thinking, emotion and language controls. 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
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; problems with the precise movements of the hands, arms, feet and legs; trouble swallowing or synchronized eye movements; and changes in the rate of speech.

Brainstem: The brainstem is the lower part of the brain that is connected to the spinal cord. It has 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. Moreover, most of the cranial nerves (described below) starting at the brainstem.

The brain stem is divided into 3 main parts: the midbrain, pons and medulla.

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 that develop tumors usually do not cause symptoms on both sides of the body (for example, weakness or numbness in the legs). This is different from the symptoms of most brain tumors, which often affect only one side of the body.

The nerves supplying arms leave the spinal cord in the neck (cervical spine). Nerves to the legs, intestines, bladder and spinal cord branch back (thoracic and lumbar spine). Tumors of the spinal cord in the neck (cervical spine) 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: The cranial nerves extend directly from the base of the brain (as opposed to the output of the spinal cord). These nerves carry signals directly between the brain and face, eyes, tongue, mouth, and some other areas.

The most common tumors of the cranial nerves in children are called optical gliomas, which are tumors of the optic nerve (the largest nerve that runs between the brain and each eye). These tumors cause vision problems. Tumors that start in other cranial nerves can cause double vision; 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 can be 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 known as a group called gliomas times.

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 pathway through which the cerebrospinal fluid (CSF) flows. 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. The most common tumors that come from these cells are called medulloblastomas, which begin in the cerebellum.

Meninges: These are layers of tissue that cover and protect the brain and spinal cord. The meninges help form the spaces through which CSF travels. 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. Tumors that start here include choroid plexus papillomas and carcinomas of the choroid plexus.

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.