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[neuroblast + -oma]
A malignant tumor that arises in neuroendocrine cells of the sympathetic nervous system.
The disease occurs in about 1 in 100,000 children, usually under the age of 2, and almost always under the age of 5. It is more often diagnosed in boys than in girls.
Neuroblastoma typically develops in cells in the adrenal glands or in cells near the spinal cord or other cells that originate in the embryonic neural crest. The disease sometimes occurs in families. It often arises as a spontaneous mutation in a specific lymphoma kinase.
SYMPTOMS AND SIGNS
Nonspecific symptoms, such as fever, abdominal swelling, loss of appetite, malaise, pain, excessive sweating, tachycardia, and weight loss are characteristic of neuroblastoma. When the disease metastasizes, it may cause symptoms in the organs it invades, e.g., bone pain when it spreads to the skeleton; cough or shortness of breath if it spreads to the lungs; weakness or paralysis if it spreads to nerves or the spinal cord. An unusual feature of neuroblastoma and a small number of other tumors is the paraneoplastic opsoclonus-myoclonus-ataxia syndrome, in which children affected by the tumor have involuntary jerking movements of the limbs, the trunk, and the eyes.
SEE: opsoclonus-myoclonus syndrome
Neuroblastomas release catecholamines into the blood. Elevated dopamine, homovanillic acid, or vanillylmandelic acid suggest the diagnosis. Imaging studies with metaiodobenzylguanidine (MIBG) can identify tumors like neuroblastoma. Microscopic examination of a biopsy specimen confirms the tumor type as well as its aggressiveness (characterized by its mitosis-karyorrhexis index, the number of active mitoses in tumor cells, and the degree to which the tumor cell nuclei are disintegrating). Chromosomal duplications or duplications of segments of chromosomes in tumor cells can be used to identify tumors that are more or less aggressive.
A localized neuroblastoma (one that has not metastasized) can be surgically removed. Metastatic cancer may require chemotherapy and radiotherapy in addition to surgical debulking. Treatment with retinoid compounds, such as isotretinoid, may make malignant cells in neuroblastomas differentiate into normal cells. Stem cell transplantation for very advanced disease or immunotherapy is sometimes employed. Some research has suggested that using MIBG bound to radioactive iodine (131I) may allow a targeted approach to antitumor therapy.
IMPACT ON HEALTH
As many as a quarter of all neuroblastomas prove fatal. Children over the age of 4 at the time of diagnosis and children with widespread disease or unfavorable prognostic markers have the greatest risk of dying. Cancer survivors are prone to develop lasting side effects from chemotherapy, and a significant percent of treated patients have a second diagnosis of cancer by their 20s or 30s. Long-term follow-up of treated patients is advisable. Some tumors regress spontaneously; this phenomenon seems to occur more often when the disease is identified in young infants.
Because the disease strikes infants and very young children, it poses grave emotional burdens on parents and other family members. Counseling and psychological support for the child and family may help them cope with the stress of the illness as well as its treatment and aftermath.