Neuroblastoma is the most common extracranial soli cancer in childhood and the most common cancer in infancy, with an annual incidence of about 650 new cases per year in the US. Close to 50 percent of neuroblastoma cases occur in children younger than two years old. It is a neuroendocrine tumor, arising from any neural crest element of the sympathetic nervous system or SNS. A branch of the autonomic nervous system, the SNS is a nerve network that carries messages from the brain throughout the body and is responsible for the fight-or-flight response and production of adrenaline or epinephrine. Its solid tumors, which take the form of a lump or mass, commonly begin in one of the adrenal glands, though they can also develop in nerve tissues in the neck, chest, abdomen, or pelvis. Esthesioneuroblastoma, also known as olfactory neuroblastoma, is believed to arise from the olfactory epithelium and classification remains controversial. Since it is not a sympathetic nervous system malignancy it is a distinct clinical entity not to be confused with neuroblastoma.