A 45-year-old man presented to our department for evaluation of a depressed lesion in the stomach, which was initially detected during screening endoscopy for gastric cancer. He had no symptoms of epigastric pain, indigestion, or diarrhea. Endoscopy revealed a discolored, depressed lesion, measuring approximately 20 mm in diameter, located on the lesser curvature of the gastric lower body (Figure 1). Magnifying endoscopy with narrow-band imaging revealed disappearance of normal pit structures in some areas, and abnormally thickened blood vessels were observed (Figure 2). Endoscopic ultrasonography revealed that the lesion was confined to the mucosal and submucosal layers of the stomach. Endoscopic biopsy revealed eosinophilic amorphous materials deposited in the lamina propria mucosae, and Congo red staining identified amyloid proteins. Tests for Helicobacter pylori showed negative results. Other studies, such as serum and urine protein electrophoresis, skull and spine radiography, thoracic, abdominal and pelvic computed tomography, echocardiography, colonoscopy with biopsy, and bone marrow biopsy, showed no systemic involvement of amyloidosis. Therefore, endoscopic submucosal dissection was performed for localized gastric amyloidosis (Figure 3). Histopathological examination revealed deposition of eosinophilic amorphous materials in the lamina propria mucosae and submucosa, which were positive for Congo red staining (Figure 4). Congo red staining performed after potassium permanganate incubation confirmed the light chain amyloid type. Because the localized gastric amyloidosis was completely resected and there was no evidence of systemic