Background <p>Gastritis cystica profunda (GCP) is a rare gastric condition characterized by glandular hyperplasia and cystic dilatation extending from the gastric mucosa into the submucosa. It is considered a potential precancerous lesion, yet its diagnosis remains challenging due to the absence of distinct clinical manifestations. Notably, chronic Helicobacter pylori infection may contribute to its pathogenesis through sustained mucosal inflammation.</p> Case presentation <p>A 63 year-old male underwent gastroscopy, which revealed a submucosal protrusion lesion on the lesser curvature of the posterior gastric antrum. Microvascular thickening on the lesion surface was detected through narrow-band imaging. In the endoscopic ultrasonography, multiple hypoechoic to anechoic lesions arising from the submucosal layer were identified, and a space-occupying lesion in the gastric antrum was detected using contrast-enhanced abdominal computed tomography. Endoscopic submucosal dissection was performed, and varying degrees of cystic dilatation of mucosal and submucosal glands were confirmed in histopathological examination, establishing the diagnosis of GCP.</p> Conclusion <p>GCP may present as a submucosal tumor-like lesion on white-light endoscopy, with histopathological assessment remaining the diagnostic gold standard. Endoscopic submucosal dissection serves as a safe and effective therapeutic approach and can be considered a first-line treatment option.&#xa0;</p>