A 60-year-old male patient presented to the gastroenterology clinic due to epigastric pain, heartburn and distension. His anamnesis revealed that these complaints had been present for about a year and that he was on medication due to them. In his medical history, he had only hypertension. His physical examination and laboratory test results were normal. Abdominal ultrasonography was normal as well. Based on these findings, upper gastrointestinal system endoscopy was planned. During endoscopic examination, an approximately 2 cm polyp with a lobulated surface was detected in the proximal gastric corpus and polypectomy was performed. Microscopic examination revealed a polyp consisted of glands, some of which presented cystic dilatation, and arranged back-to-back under gastric foveolar epithelium that covered the surface. On immunohistochemical examination, while MUC 5AC was positive in the gastric foveolar epithelium that covered the surface of the polyp and was negative in glandular structures, MUC 6 was found to be positive in the glands and negative on the surface of the polyp (fig. 1, fig. 2). Since the morphological appearance of the glands and the immunohistochemical MUC 6 positivity were consistent with pyloric glands, the lesion was reported as 'pyloric gland adenoma'. A gland that was covered with cells having hyperchromatic nuclei and presented pseudostratification in a focal area inside the polyp attracted attention. This area was considered as high-degree dysplasia since hyperchromatic nuclei had reached up to cell surface (fig. 3).