抄録
A 84-year-old man on hemodialysis for end-stage renal disease was admitted to our hospital with the chief complaint of anemia. Anti-parietal cell antibody was positive on blood test. On gastroendoscopy, three variable forms of elevated lesions were noted, and macro findings were compatible with autoimmune gastritis. Biopsy specimens revealed microscopic proliferation of atypical cells with round nuclei and clear cytoplasm in trabecular pattern. Immunohistochemical staining showed these tumor cells to be uniformly positive for chromogranin A and synaptophysin. Together with MIB1 (Ki67) labeling index result which was not low (>2%) , well differentiated neuroendocrine carcinoma was suspected. Computed tomography showed no signs of metastasis in the liver or extra-gastric lymph nodes. Total gastrectomy was performed. Three tumors were observed. 15mm diameter polyp on the great curvature of upper gastric body was reddish and irregular surface, another was a flat elevated 10mm diameter lesion on the anterial wall of upper gastric body with slight depression, the third was a 40mm diameter submucosal tumor like lesion with a reddish depression on the lesser curvature of upper gastric body. They were all positive for chromogranin A and synaptophysin. MIB1 index were all more than 2%.Thus, they were diagnosed to be differentiated neuroendocrine carcinomas as well. From findings compatible with autoimmune gastritis, and endocrine cell micronests observed on pathology, cancerization from well differentiated neuroendocrine tumor derived from antoimmune gastritis was considered. We also suspect that the laxation between the tumor and the muscle layer by peristalsis made the tumor pedunculated, and ischemic change due to the pressure from growing tumor made the mucosa depressive.
