Atrophic gastritis and pre-malignant gastric lesions

Atrophic gastritis and intestinal metaplasia are considered to be precancerous conditions as they constitute the background in which dysplasia and intestinal-type gastric adenocarcinoma may develop. The development of the intestinal-type gastric adenocarcinoma represents the end step of an inflammation-metaplasia-dysplasia-carcinoma sequence, called the Correa cascade of multistep gastric carcinogenesis. Atrophic gastritis is associated also with type 1 gastric carcinoid whose major pathogenetic factor is hypergastrinemia. Gastrin acts as a growth factor for enterochromaffin-like cells, which in atrophic gastritis are chronically induced to proliferate, and, through a multistep process passing from hyperplasia to dysplasia, carcinoid may develop. Atrophic gastritis is a chronic disorder occurring in up to 8% of the general population. The positivity of autoantibodies against parietal cells and/or intrinsic factor, the compresence of autoimmune diseases as thyroid autoimmune disease or type 1 diabetes are frequently observed. A frequent clinical presentation of atrophic gastritis is pernicious anemia arising from vitamin B12 malabsorption as a consequence of intrinsic factor deficiency. Also iron deficiency anemia may be associated with atrophic gastritis due to iron malabsorption as a consequence of reduced gastric acid secretion together with normal or low cobalamin levels. Pernicious anemia, the possible end-stage of atrophic gastritis, is considered an autoimmune disorder. To date, there are no clear universally accepted criteria to define autoimmune gastritis and to distinguish this clinical entity from chronic Helicobacter pylori (H. pylori)-driven atrophic gastritis. In the last years, many data emerged from several studies on prevalence of atrophic gastritis and intestinal metaplasia, risk of progression of these conditions to gastric neoplasms, clinical features and detection of these precancerous changes in the gastric mucosa. The purpose of this review was to focus on these issues.