Neuroblastoma is a rare cancer that grows from immature nerve cells. It is usually found in infants and children before the age of 10, but may also occur in adults. Cancer in children is much rarer than cancer in adults. According to the American Cancer Society (ACS), children’s cancers account for 1 percent of all cancers. While rare in general, neuroblastoma is the most common type of cancer in infants by far, and the third most common cancer in children, after leukemia and brain tumors. About 650 new cases occur each year, according to the ACS.

Neuroblastomas develop from immature nerve cells called neuroblasts. Neuroblasts are cells remaining from embryonic and fetal nerve tissue that normally mature into cells of the adrenal glands, the brain and the spinal cord. The cells that do not mature can grow into:

• Mature nerve cells at a later time or disappear, thereby resolving naturally.
  
  
• Ganglioneuroma. A benign tumor that develops when neuroblasts mature into masses called ganglion cells and then stop multiplying.
  
  
• Ganglioneuroblastoma. A tumor containing malignant and benign cells. This form of tumor contains cells that are similar to ganglioneuroma cells. It also contains malignant neuroblasts.
  
  
• Neuroblastomas. A tumor composed entirely of malignant cells.

Neuroblastomas most often affect the sympathetic nervous system, which controls vital life functions such as heart rate, blood pressure, digestion and production of some hormones. They may also affect the tissues of the adrenal glands, which produce and release adrenaline and cortisone. 

Because of their origin in the sympathetic nervous system or adrenal glands, neuroblastomas can affect vital involuntary body functions such as heart rate, blood pressure, digestion, blood sugar, stress response and specific emergency hormone production. The cells grow rapidly and expand into a mass that compresses the organs around it, affecting their functioning.

According to the ACS, the tumors originate in adrenal gland tissue in approximately one-third of neuroblastoma cases. The adrenal glands produce and release adrenaline and cortisone.  Catecholamines are hormones secreted by the adrenal glands and are found in high amounts in children with neuroblastoma. This can lead to problems such as high blood pressure. Neuroblastomas may also be located elsewhere, such as the neck, chest, brain or spinal cord, and can spread to the liver, the lymph nodes, lungs, bones and bone marrow. At the time of diagnosis, 7 out of 10 cases have metastasized.

More than 90 percent of patients diagnosed with neuroblastoma that is localized or concentrated in one area can be cured, according to the National Cancer Institute (NCI). However, even in the advanced stages, children can respond favorably to treatment. When neuroblastoma has metastasized the prognosis is significantly less favorable. Factors included in prognosis (recovery outcome) are:

• Patient’s age at diagnosis. The younger the patient, the better the outcome. About 40 percent of patients are diagnosed before their first birthday.
  
  
• Stage of the disease.  Higher stage cancer indicates the disease has spread to other areas of the body, which relates to a poorer prognosis.
  
  
• Regional lymph node metastasis after one year of age.

According to the ACS, children are diagnosed with the condition before the age of five in 90 percent of cases, and rarely after 10 years (about 2 percent).