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Hello, it's Sarah again. I'm hoping this post will bring more awareness to the nature of Neuroblastoma, the form of cancer Nikki and I are Blogathoning for. There are, as it goes with medical maladies, a lot of unfamiliar terms, and I hope this post will give everyone a clearer picture.

What Is Neuroblastoma?

Neuroblastoma is a form of cancer that occurs in infants and young children. It is rarely found in children older than 10 years. The cells of this cancer usually resemble very primitive developing nerve cells found in an embryo or fetus. (The term neuro indicates "nerves," while blastoma refers to a cancer that affects immature or developing cells).

Neurons (nerve cells) are the main component of the brain and spinal cord and of the nerves that connect them to the rest of the body. These cells are essential for thinking, sensation, and movement. There is a part of the nervous system that we are rarely aware of, called the autonomic nervous system, which controls involuntary body functions such as heart rate, blood pressure, and digestion. The sympathetic nervous system is a part of the autonomic nervous system. It includes:

* nerve fibers that run alongside the spinal cord
* clusters of nerve cells called ganglia (plural of ganglion) at certain points along the path of the nerve fibers
* nerve-like cells found in the medulla (center) of the adrenal glands. The adrenals are triangular-shaped glands located above the kidneys. The hormone adrenaline comes from the cells in the adrenal gland.

Most neuroblastomas (about two thirds) start in the abdomen. About one third of neuroblastomas start in the adrenal glands and another third begin in the sympathetic nervous system ganglia of the abdomen. The rest start in sympathetic ganglia of the chest or neck or in the pelvis. Some can start in the spinal cord. Rarely, a neuroblastoma may have spread so extensively by the time it is found that doctors are unable to determine exactly where it started.

Not all childhood autonomic nervous system tumors are malignant (cancerous). There is a benign tumor called ganglioneuroma which is composed of mature ganglion and nerve sheaths that do not continue to grow.

Ganglioneuroblastoma is a tumor that has both malignant and benign parts. It contains neuroblasts (immature nerve cells) that can grow and spread abnormally, as well as areas of benign tissue that are similar to ganglioneuroma.

Ganglioneuromas are usually removed by surgery and carefully examined under a microscope to be certain they do not have areas of ganglioneuroblastoma. If the final diagnosis is ganglioneuroma, no additional treatment is needed. In contrast, ganglioneuroblastomas are treated the same as neuroblastomas (see "How Is Neuroblastoma Treated?").

Neuroblastoma is a unique cancer in many ways. It is one of the few cancers in children that release hormones that can cause strange changes in the body, such as constant diarrhea. It can also cause changes in the some functions of the brain, such as opsoclonus (rotary movements of the eyes) and myoclonus (spastic jerks of the muscles).

These changes are called paraneoplastic syndromes.

The tumor itself can behave strangely. Sometimes the cells die without any cause and the tumor disappears. This is part of a normal process known as programmed cell death (apoptosis), the normal process that occurs when cells die. This tumor disappearance is much more common in very young infants than in older children. Another behavior that is unusual for childhood tumors is that the cells sometimes mature spontaneously to normal ganglion cells and stop dividing. This causes the tumor to become a ganglioneuroma, which is benign (non-cancerous).

Thanks to www.cancer.org for the information.