What happened, in summary

A 60-year-old woman was referred for severe anemia after an episode of black stool. Imaging and endoscopy showed markedly enlarged stomach folds consistent with Menetrier disease, along with a 40-mm raised lesion in the gastric body. Endoscopic ultrasound suggested that the lesion was confined to the stomach lining, but a small biopsy could not definitively distinguish tumor from inflammatory change.

Because the endoscopic appearance remained highly suspicious for cancer, the lesion was removed in one piece by endoscopic submucosal dissection. Examination of the full specimen showed a well-differentiated tubular gastric adenocarcinoma confined to the mucosal layer, without lymphovascular invasion or ulceration. Both the lateral and deep resection margins were negative, supporting complete curative resection. The surrounding stomach tissue showed the characteristic changes of Menetrier disease.

She did not need additional gastric-cancer treatment. Follow-up endoscopy was performed twice a year for 3 years and showed no recurrence. During the same period, the enlarged gastric folds regressed without Menetrier-specific medication, and her anemia and low protein levels gradually improved. The remission of the gastric changes was maintained through the latest surveillance.