Neuroblastoma is one of the most common childhood cancers after leukemia and brain tumor, and is a typical cancer originating in the abdomen of children. It most frequently occurs in children aged one year or younger, and most cases are found in children aged five years or younger.
Neuroblastoma often begins in organs called the adrenal glands on top of each kidney and nervous tissue called the sympathetic ganglia along both sides of the vertebral column (spine). Although the adrenal glands and the sympathetic ganglia are at the dorsal side (back) of the body, the tumor (neuroblastoma) grows toward the ventral side (front) of the body. Therefore, the tumor is found as an abdominal mass. Since the sympathetic ganglia form a chain from the neck to the pelvis, a tumor can arise from the neck, chest, or pelvis. Mass screening for neuroblastoma using urine samples was once conducted across Japan to detect the tumor early, but it has been suspended at present. Some neuroblastomas are incidentally detected at medical examinations and some at the time of x-ray examinations. In more than half of the children with neuroblastoma, the tumor has metastasized (spread) and is only found based on symptoms related to metastasis. For example, some children walk awkwardly because of pain in the hands and feet caused by metastasis to the bone, and some have swollen eyelids because of metastasis to the bone behind the eye. Other ambiguous signs, including fever, ill complexion, bad mood, or lack of energy, may persist.