DISTINCT PATTERNS OF CHRONIC GASTRITIS ASSOCIATED WITH CARCINOID AND CANCER AND THEIR ROLE IN TUMORIGENESIS

A series of 60 gastric endocrine tumors comprised 44 body-fundus argyr ophil carcinoids, of which 23 arose in a background of hypergastrinemi a and type A chronic atrophic gastritis (A-CAG), mainly with histologi c patterns suggestive of an autoimmune process. Only 22 percent (compa red with 19 percent of 58 tumor-free A-CAG cases) of 36 carcinoids and 21 percent of 19 A-CAG carcinoids investigated had Helicobacter pylor i (HP) colonization, against 50 percent of 14 CAG-associated neuroendo crine carcinomas or mixed endocrine-exocrine tumors, 84 percent of 150 cases with early gastric cancer (p < 0.001 versus carcinoids), mostly with B- or AB-type CAG, 76 percent of 97 tumor-free AB-CAG, and 95 pe rcent of 151 tumor-free B-CAG cases. Secondary hypergastrinemia and lo cal mechanisms activated by chronic autoimmune gastritis are among fac tors involved in the pathogenesis of relatively indolent CAG-associate d carcinoids, whereas active HP gastritis in cooperation with environm ental carcinogens may likely cause more severe epithelial transformati on, leading to ordinary cancer and, possibly, to neuroendocrine carcin omas or mixed endocrine-exocrine tumors.