A 70-year-old male had undergone esophagogastroduodenoscopy (EGD) every year for evaluation of chronic gastritis since 2007. Endoscopy showed an area of discoloration with submucosal tumor-like shape, measuring 10mm on the anterior wall in the upper portion of the stomach. It exhibited dilated superficial vessels with branching architecture. Biopsy had been performed several times, but there was no evidence of malignancy. In 2015, EGD and biopsy were performed again. From pathological examination, gastric adenocarcinoma of the fundic gland type was suspected. We performed endoscopic submucosal dissection and achieved complete resection. The final pathological diagnosis was gastric adenocarcinoma of fundic gland mucosa type. The shape and diameter of the lesion had not significantly changed over the eight-year period. Here we report a rare case of gastric adenocarcinoma of the fundic gland mucosa type that showed very slow progression.
