Neuroblastoma

What Is It?

Of all the childhood cancers, neuroblastoma is the most common tumor to develop outside the brain. It accounts for 8 percent to 10 percent of childhood cancers. The average age at diagnosis is 2 years old.

Neuroblastomas form in the nerve cells that are responsible for the body's ability to react to a life-threatening emergency, called the "fight-or-flight" response. This nerve network is called the sympathetic nervous system.

Neuroblastomas usually form in one of two parts of the sympathetic nervous system:

• The adrenal glands — These glands in the abdomen produce the hormone adrenaline, which is released in an emergency to help the body react. When a neuroblastoma develops in the adrenal gland, it typically grows into a large, firm abdominal mass that can compress nearby organs.
• The chain of sympathetic ganglia — These are collections of sympathetic nerves that lay near the backbone (spine). When a neuroblastoma develops along the sympathetic chain, it can invade nearby areas of the spine and cause injury to spinal nerves.

Neuroblastomas less commonly develop in other areas of the body, including the chest, neck and pelvis.

As a neuroblastoma grows, it has the potential to spread (metastasize) to areas away from where the cancer began, most commonly to the bone marrow, bones, liver and skin.

There is no conclusive evidence that neuroblastoma is related to any toxic chemical or environmental risk factor. Genetic (inherited) factors seem to influence the development of some neuroblastomas.

Symptoms

Symptoms of a neuroblastoma can include:

• A firm mass in the abdomen, with or without abdominal pain or discomfort
• Difficulty breathing when the abdominal mass presses upwards on the infant's chest and lungs
• Weight loss or failure to thrive
• Anemia (a low number of red blood cells)
• Fever and irritability
• Bone pain
• Neurological symptoms if the tumor damages nearby nerves, including paralysis, difficulty swallowing, difficulty walking, uncontrolled eye movements, a drooping eyelid, or jerky or uncontrolled limb movements
• Protruding eyes or dark circles around the eyes ("panda eyes")
• Symptoms caused by chemicals produced by the tumor, including high blood pressure, rapid pulse, flushing, sweating or watery diarrhea

In some cases, a child's neuroblastoma is diagnosed by chance before it causes symptoms. The tumor is discovered in the chest or abdomen when the child has an X-ray to check for some unrelated illness.