|
Neuroblastoma (NB) is the most common extracranial solid cancer in childhood and the most common cancer in infancy, with an incidence of about six hundred fifty cases per year in the U.S., and a hundred cases per year in the UK.〔(【引用サイトリンク】title=Neuroblastoma )〕 Nearly half of neuroblastoma cases occur in children younger than two years. It is a neuroendocrine tumor, arising from any neural crest element of the sympathetic nervous system (SNS). It most frequently originates in one of the adrenal glands, but can also develop in nerve tissues in the neck, chest, abdomen, or pelvis. Neuroblastoma is one of the few human malignancies known to demonstrate spontaneous regression from an undifferentiated state to a completely benign cellular appearance. It is a disease exhibiting extreme heterogeneity, and is stratified into three risk categories: low, intermediate, and high risk. Low-risk disease is most common in infants and good outcomes are common with observation only or surgery, whereas high-risk disease is difficult to treat successfully even with the most intensive multi-modal therapies available.〔 Esthesioneuroblastoma, also known as olfactory neuroblastoma, is believed to arise from the olfactory epithelium and its classification remains controversial. However, since it is not a sympathetic nervous system malignancy, esthesioneuroblastoma is a distinct clinical entity and is not to be confused with neuroblastoma. ==Signs and symptoms== 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: * In the abdomen, a tumor may cause a swollen belly and constipation. * A tumor in the chest may cause breathing problems. * A tumor pressing on the spinal cord may cause weakness and thus an inability to stand, crawl, or walk. * Bone lesions in the legs and hips may cause pain and limping. * A tumor in the bones around the eyes or orbits may cause distinct bruising and swelling. * Infiltration of the bone marrow may cause pallor from anemia. 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.〔(【引用サイトリンク】title=Neuroblastoma: Pediatric Cancers: Merck Manual Professional )〕 The most common location for neuroblastoma to originate (i.e., the primary tumor) is on 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% non-adrenal), 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). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「neuroblastoma」の詳細全文を読む スポンサード リンク
|