Phlegmonous gastritis is a rare and rapidly progressive bacterial infection of the stomach wall, with a high mortality rate. Antibiotics with or without surgical treatment are required for treatment. We present a case in which phlegmonous gastritis occurred during the diagnostic evaluation of early gastric cancer. The patient showed improvement after antibiotic treatment, but attempted endoscopic submucosal dissection failed because of submucosal pus. We immediately applied argon plasma coagulation since surgical resection was also considered a high-risk procedure because of the submucosal pus and multiple comorbidities. However, there was local recurrence two years later, and the patient underwent subtotal gastrectomy with lymph node dissection. Considering the risk of incomplete treatment immediately after recovery from phlegmonous gastritis and that recurrent disease can be more difficult to manage, delaying treatment and evaluation until after complete recovery of PG might be a better option in this particular clinical situation.
Keywords: Early gastric cancer; Endoscopic submucosal dissection; Phlegmonous gastritis.