抄録
A 50-year-old man was referred for further examination of a gastric submucosal tumor. Upper gastrointestinal endoscopy revealed an erythematous submucosal tumor measuring 5 mm in diameter in the anterior wall of the middle third of the gastric body, but no atrophy of the gastric mucosa. Biopsy of the tumor showed a well-differentiated neuroendocrine tumor ; the serum gastrin level was within normal limits and the test for anti-gastric parietal cell antibody was negative. Based on the findings, the tumor was diagnosed as a sporadic Type III gastric carcinoid. The tumor was resected en bloc by endoscopic mucosal resection using a cap-fitted panendoscope. Histology showed invasion of the submucosal layer by carcinoid cells, but no lymphatic/venous invasion, and a sufficient horizontal and vertical margin of the resected specimen. The mitosis rate was low (＜2/10HPF) and the Ki-67 labeling index was less than 2%, consistent with the histological results of the biopsy specimen. Until now, 24 months since the surgery, no local remnant lesion or metastasis has been found. As sporadic Type III gastric carcinoids behave more aggressively than Type I and II tumors, the guidelines recommend radical gastrectomy plus regional lymphadenectomy. However, surgical resection might possibly be overtreatment for some cases, and further examination is necessary to determine the precise indications of endoscopic resection for sporadic Type III gastric carcinoids.
