Neuroblastoma is the most common malignant (cancerous) extracranial solid  tumor of childhood. It develops from the tissues that form the sympathetic nervous system, which is the part of the nervous system that regulates involuntary body functions.

The tumor usually begins in the nerve tissues of the adrenal gland (above the kidney), but may also begin in nerve tissues of the neck, chest or pelvis.

Although neuroblastoma often is present at birth, it generally is not detected until the tumor begins to grow and compress the surrounding organs.

Cancer cells can metastasize (spread) quickly to other areas of the body, such as lymph nodes, liver, lungs, bones, the central nervous system and bone marrow. Close to 70 percent of children diagnosed with neuroblastoma will have metastatic disease.

Approximately 650 children in the United States are diagnosed with this tumor each year, and most children affected by the disease are diagnosed before age 5. Neuroblastoma occurs with slightly more frequency in males than in females.