Pyloric Gland Adenoma Covered by Normal Mucosa in the Stomach

CASE REPORT The patient was a 78-year-old man. On upper periodic endoscopy, an elevated lesion with a diameter of 18 mm with 1 opening was seen in the anterior wall of the lesser curvature of the gastric middle body by white light observation (Figure 1). On narrow-band imaging with magnifying endoscopy, no atypical papillary mucosa was observed in and around the opening (Figure 2). Endoscopic ultrasonography showed a low-echoic area in the submucosal layer (Figure 3). There were no malignant findings in the biopsy. The tumor showed an increasing trend compared with the previous evaluation. Endoscopic submucosal dissection was performed to make a definitive diagnosis.Figure 1.: On upper periodic endoscopy, an elevated lesion with a diameter of 18 mm with 1 opening observed in the anterior wall of the lesser curvature of the gastric middle body by white light observation.Figure 2.: Narrow-band imaging with magnifying endoscopy showed no atypical papillary mucosa in and around the opening.Figure 3.: Endoscopic ultrasonography showed a low-echoic area in the submucosal layer.Histological examination revealed that the covering epithelial cells had a papillary structure, but no atypia was observed. In the deep layer of the gastric mucosal epithelium and submucosal layer, most of the glandular cells had round nuclei with prominent nucleoli and mucinous columnar cytoplasm, reminiscent of pyloric gland cells, and they were positive for MUC5AC and MAC6 but negative for pepsinogen (Figure 4). The lesion was diagnosed as pyloric gland adenoma.Figure 4.: In the deep layer of the gastric mucosal epithelium and submucosal layer, most of the glandular cells had round nuclei with prominent nucleoli and mucinous columnar cytoplasm, reminiscent of pyloric gland cells.There is 1 reported case of pyloric gland adenoma covered by normal mucosa in the stomach.1 Endoscopists should pay attention to whether there is a possibility of pyloric gland adenoma when finding elevated lesions covered by normal mucosa in the stomach. DISCLOSURES Author contributions: S. Abiko wrote the manuscript and is the article guarantor. K. Nakajima, K. Hirata, K. Suzuki, K. Kinoshita, K. Hatanaka, Y. Yamamoto, H. Naruse, and N Sakamoto edited the manuscript. Acknowledgments: We thank Satoru Munakata in the Department of Pathology, Hakodate Municipal Hospital for his kind support and advice. We are very grateful to the wonderful staff in the endoscopic room, outpatient care, and ward of Hakodate Municipal Hospital. Financial disclosure: None to report. Informed consent was obtained for this case report.