RESUMO
BACKGROUND: Submucosal protuberance caused by fish bone insertion into the digestive tract has rarely been reported. These cases usually include patients with clear signs such as a history of fish intake, pain, and dysphagia, as well as positive findings on endoscopy and imaging. Here, we report a case of a fish bone hidden in the submucosal protuberance of the gastric antrum during endoscopic submucosal dissection without preoperative obvious positive signs. CASE SUMMARY: A 58-year-old woman presented with epigastric pain for the past 20 d and a submucosal protuberance. Abdominal computed tomography and endoscopic ultrasonography did not indicate the presence of a fish bone. We assumed the cause to be an ordinary submucosal eminence and performed an endoscopic submucosal dissection to confirm its essence. During the operation, a fish bone approximately 20 mm in length was found incidentally. CONCLUSION: Our report could potentially prevent the oversight of embedded fish bones and associated adverse effects in patients with similar presentation.