Abstract
Background: Heterotopic gastric mucosa(HGM)is a congenital anatomical variation. It can occur in various tissues and organs of the gastrointestinal tract. Part of the HGM appeared as a solitary, sessile submucosal lesions covered with normal mucosa, and because it was relatively rare, thereby resulting in some HGM to be easily missed or misdiagnosed. We report on a case of heterotopic gastric mucosa in gastric propria muscularis.Case presentation: A 32-year-old man with abdominal distension for one month. Upper gastrointestinal endoscopy revealed hemispherical lesion covered with smooth mucosa located in gastric antrum. Endoscopic ultrasound (EUS) revealed that it might be derived from the submucosa, with no echogenic nodules, and a partition is visible inside. Endoscopic submucosal dissection (ESD) was performed and histological examination revealed scattered heterotopic mucosal glands (HGG) located in the propria muscularis. Regular follow-up, the patient's abdominal distension was significantly relieved.Conclusion: HGM of the type of submucosal tumor-like lesion is rare. EUS is a well-established method for submucosal lesion. On EUS, these lesions showed cystic anechoic central core in the submucosa with no solid component,which is similar to gastric cyst. Therefore, this requires us to be alert to the possibility of HGM in order to further evaluate and treat, and if necessary, it can be removed by ESD.