Misdiagnosis of gastric oxyntic gland adenoma as hyperplastic polyp: A case report

Gastric oxyntic gland adenoma is a rare neoplasm often misdiagnosed as a hyperplastic or fundic gland polyp due to nonspecific endoscopic features and the limitations of superficial biopsies, leading to diagnostic delays. In 2020, a gastroscopy of a 47-year-old man revealed a 0.5 cm lesion that was diagnosed as a hyperplastic polyp by superficial biopsy. By 2022, the lesion had enlarged to 1.0 cm exhibiting firmness, bleeding tendency, and disrupted submucosal layers on endoscopic ultrasound. Repeat biopsies again suggested hyperplasia. Endoscopic submucosal dissection was performed, confirming the diagnosis of gastric oxyntic gland adenoma. Additional surgical resection confirmed negative margins, and no recurrence at the three-year postoperative follow-up. However, endoscopic ultrasound revealed localized thickening (1.2 mm) of the muscularis mucosae at the gastric lesser curvature, likely representing post-procedural fibrosis. The patient was clinically asymptomatic, and was advised to continue annual endoscopic monitoring. This case highlights the necessity of deep biopsy or complete resection for diagnosis. We recommend long-term endoscopic surveillance post-resection and heightened clinical vigilance to mitigate misdiagnosis risks.