What is esophagogastric mucosal heterotopia Esophagogastric mucosal heterotopia is a rare congenital embryonic residual lesion that can occur in any part of the esophagus, most commonly in the upper 1/3 of the esophagus, near the level of the cricopharyngeal muscle. The etiology of the disease is not completely clear, but it is mostly thought to be related to congenital developmental abnormalities: at the time of germination, the surface of the esophagus is replaced by a complex squamous epithelium, and if this replacement process is incomplete, the embryonic gastric mucosa may remain in the esophagus and ectopic esophagogastric mucosa may occur. The prevalence of Barrett’s esophagus is significantly higher. Therefore, ectopic esophagogastric mucosa may be a dual-etiology disease, caused by a combination of acquired acid reflux irritation and other factors based on an underlying congenital embryonic developmental abnormality. In recent years, with the widespread availability of electronic gastroscopy and improved examination and treatment techniques, an increase in cases of this disease has been detected. Diagnostic points of esophagogastric mucosal ectasia 1. asymptomatic or uncomfortable swallowing; 2. endoscopy showing orange-red mucosa in the upper esophagus; 3. pathological biopsy showing gastric fundic glands containing acid-producing cells. The clinical manifestations of esophagogastric mucosal ectopia are not specific, and most of them are only found incidentally during microscopic examination, but sometimes acid-related symptoms such as retrosternal discomfort and painful swallowing can also occur. Endoscopy is the main tool to diagnose this disease, but it is often missed due to its high location. The key to improving the detection rate is to increase the endoscopist’s awareness of the disease. The typical lesion is a well-defined oval or round orange-red mucosa in the upper esophagus that is clearly demarcated from the surrounding esophageal mucosa; in a few cases, a polypoid or bulging lesion may be present. Biopsy pathology may reveal fundic glands. Some pyloric glands are also visible. Carcinoma of the esophageal ectopic gastric mucosa is extremely rare, but is easily combined with H. pylori infection. The disease is easily confused with Barrett’s esophagus, which can be differentiated by SCJ (Z-line) upstaging and intestinalization. The main points of treatment for esophagogastric mucosal ectasia are 1) asymptomatic patients do not need special treatment; 2) acid suppression therapy for combined reflux symptoms; 3) endoscopic treatment for frequent symptoms. Patients with ectopic esophagogastric mucosa can be treated without special treatment if they have no clinical symptoms, but because ectopic gastric mucosa has the function of acid secretion, it can cause esophageal ulcer, bleeding or complication of GERD, and acid suppression therapy can be carried out with PPI preparations such as Nexium or Perlite. Most patients can be relieved by conventional doses of acid therapy, and endoscopic treatment is feasible for patients with frequent symptoms, heavy psychological burden or suspected cancer. It includes endoscopic laser, argon knife and high-frequency electrocautery, etc. If necessary, endoscopic mucosal dissection is feasible. Surgery can be considered for serious complications such as esophagogastric mucosal ectasia with stenosis and perforation.