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Barrett's esophagus (British English: Barrett's oesophagus), sometimes called Barrett syndrome, Barrett esophagus, or columnar epithelium lined lower oesophagus (CELLO), refers to an abnormal change (metaplasia) in the cells of the lower portion of the esophagus. It is characterized by the replacement of the normal stratified squamous epithelium lining of the esophagus by simple columnar epithelium with goblet cells (which are usually found lower in the gastrointestinal tract). The medical significance of Barrett's esophagus is its strong association (about 0.5% per patient-year) with esophageal adenocarcinoma, a very often deadly cancer, because of which it is considered to be a premalignant condition. The main cause of Barrett's esophagus is thought to be an adaptation to chronic acid exposure from reflux esophagitis. The incidence of esophageal adenocarcinoma has increased substantially in the Western world in recent years.〔 The condition is found in 5–15% of patients who seek medical care for heartburn (gastroesophageal reflux disease), although a large subgroup of patients with Barrett's esophagus do not have symptoms.〔 Diagnosis requires endoscopy (more specifically, esophagogastroduodenoscopy, a procedure in which a fibreoptic cable is inserted through the mouth to examine the esophagus, stomach, and duodenum) and biopsy. The cells of Barrett's esophagus, after biopsy, are classified into four general categories: nondysplastic, low-grade dysplasia, high-grade dysplasia, and frank carcinoma. High-grade dysplasia and early stages of adenocarcinoma can be treated by endoscopic resection and new endoscopic therapies such as radiofrequency ablation, whereas advanced stages (submucosal) are generally advised to undergo surgical treatment. Nondysplastic and low-grade patients are generally advised to undergo annual observation with endoscopy, with radiofrequency ablation as a therapeutic option. In high-grade dysplasia, the risk of developing cancer might be at 10% per patient-year or greater.〔 The condition is named after the Australian-born British thoracic surgeon Norman Barrett (1903–1979), who described it in 1950. ==Signs and symptoms== The change from normal to premalignant cells that indicate Barrett's esophagus does not cause any particular symptoms. Barrett's esophagus, however, is associated with these symptoms: * frequent and longstanding heartburn * trouble swallowing (dysphagia) * vomiting blood (hematemesis) * pain under the sternum where the esophagus meets the stomach * unintentional weight loss because eating is painful The risk of developing Barrett's esophagus is increased by central obesity (vs. peripheral obesity). The exact mechanism is unclear. The difference in distribution of fat among men (more central) and women (more peripheral) may explain the increased risk in males. 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「Barrett's esophagus」の詳細全文を読む スポンサード リンク
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