Neuroblastoma

Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands, but can also develop in the neck, chest, abdomen, or spine. Symptoms may include bone pain, a lump in the abdomen, neck, or chest, or a painless bluish lump under the skin. Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands, but can also develop in the neck, chest, abdomen, or spine. Symptoms may include bone pain, a lump in the abdomen, neck, or chest, or a painless bluish lump under the skin. Occasionally, neuroblastoma may be due to a mutation inherited from a person's parents. Environmental factors have not been found to be involved. Diagnosis is based on a tissue biopsy. Occasionally it may be found in a baby by ultrasound during pregnancy. At diagnosis, the cancer has usually already spread. The cancer is divided into low-, intermediate-, and high-risk groups based on a child's age, cancer stage, and what the cancer looks like. Treatment and outcomes depends on the risk group a person is in. Treatments may include observation, surgery, radiation, chemotherapy, or stem cell transplantation. Low-risk disease in babies typically has a good outcome with surgery or simply observation. In high-risk disease, chances of long-term survival, however, are less than 40% despite aggressive treatment. Neuroblastoma is the most common cancer in babies and the third-most common cancer in children after leukemia and brain cancer. About one in every 7,000 children is affected at some time. About 90% of cases occur in children less than 5 years old and it is rare in adults. Of cancer deaths in children, about 15% are due to neuroblastoma. The disease was first described in the 1800s. The first symptoms of neuroblastoma are often vague, making diagnosis difficult. Fatigue, loss of appetite, fever, and joint pain are common. Symptoms depend on primary tumor locations and metastases if present: Neuroblastoma often spreads to other parts of the body before any symptoms are apparent, and 50 to 60% of all neuroblastoma cases present with metastases. The most common location for neuroblastoma to originate (i.e., the primary tumor) is in the adrenal glands. This occurs in 40% of localized tumors and in 60% of cases of widespread disease. Neuroblastoma can also develop anywhere along the sympathetic nervous system chain from the neck to the pelvis. Frequencies in different locations include: neck (1%), chest (19%), abdomen (30% nonadrenal), or pelvis (1%). In rare cases, no primary tumor can be discerned. Rare but characteristic presentations include transverse myelopathy (tumor spinal cord compression, 5% of cases), treatment-resistant diarrhea (tumor vasoactive intestinal peptide secretion, 4% of cases), Horner's syndrome (cervical tumor, 2.4% of cases), opsoclonus myoclonus syndrome and ataxia (suspected paraneoplastic cause, 1.3% of cases), and hypertension (catecholamine secretion or renal artery compression, 1.3% of cases). The cause of neuroblastoma is not well understood. The great majority of cases are sporadic and nonfamilial. About 1–2% of cases run in families and have been linked to specific gene mutations. Familial neuroblastoma in some cases is caused by rare germline mutations in the anaplastic lymphoma kinase (ALK) gene. Germline mutations in the PHOX2B or KIF1B gene have been implicated in familial neuroblastoma, as well. Neuroblastoma is also a feature of neurofibromatosis type 1 and the Beckwith-Wiedemann syndrome.