A malignant growth comprising embryonic nerve cells. It may start in any part of the AUTONOMIC NERVOUS SYSTEM. The medulla of the adrenal gland (see under ENDOCRINE GLANDS) is a common site; secondary growths develop in other tissues. Neuroblastomas are the most common extracranial solid tumour of childhood. The incidence is around eight cases per one million children. Treatment is by surgery followed by radiotherapy and CYTOTOXIC drugs.