Atrophic gastritis and gastric carcinoid tumours.

During recent decades an increasing number of case reports have pointed at a relation between atrophic gastritis type A and gastric carcinoid. This relation has now been quantitatively documented in endoscopic screening studies. Among patients with pernicious anaemia the prevalence of gastric carcinoid was 2-9%. Many of these carcinoids, however, remain subclinical. The majority are broadbased polypoid tumours. Most are situated in the gastric body or fundus. Of 95 patients with atrophic gastritis and gastric carcinoid reported in the literature, 60 (63%) had multicentric tumours and 13 (14%) lymph node and/or hepatic metastases. Microscopically, the tumours, which are frequently of the enterochromaffin-like cell type, show various structural differentiations, glandular differentiation indicating malignant potential. Purely intramucosal carcinoids have been described. The precurser lesion to such "early carcinoids", as well as to infiltrating carcinoids, is probably hyperplasia of endocrine cells in the atrophic fundic mucosa. Such hyperplasias, whether nodular or diffuse, are quantitatively related to hypergastrinaemia, which is a typical feature of antrum sparing (type A) atrophic gastritis. Most tumours can be treated endoscopically, although antrectomy with abolition of hypergastrinemia may be the definitive treatment. It seems that the risk of developing gastric carcinoid 'per se' does not justify regular gastric screening in patients with type A atrophic gastritis. However, as these patients also run an increased risk of developing several benign diseases, gastric adenocarcinoma, and probably also pancreatic malignancy, regular survey in selected cases is indicated.