GASTRODUODENAL PATHOLOGY

Heliobacter pylori is one of the major causes of gastroduodenal diseas e, including gastritis, ulcers, gastric carcinoma, and mucosa-associat ed lymphoid tissue (MALT) lymphoma. We believe that there are three pa tterns of H. pylori-associated gastritis, each associated with a diffe rent outcome. Diffuse antral-predominant gastritis (DAG) has gastritis involving mainly the antrum, less intestinal metaplasia confined to t he antrum, and in the United States, is associated with 90% of the duo denal ulcers, Multifocal intestinalized pangastritis (MIP) is the most severely intestinalized of the H. pylori gastritides, and is the main risk for the development of gastric adenocarcinoma. MIP is also assoc iated with benign gastric ulcers, Nonulcer pangastritis (NUP) is also a pangastritis, but does not have an associated ulcer and has little i f any, intestinal metaplasia, NUP may rarely be the precursor to diffu se gastric adenocarcinoma, MALT lymphomas have also been found to be a ssociated with the H. pylori gastritis and may be seen with any of the three patterns. More than half of these lymphomas will regress follow ing H. pylori eradication, although it is uncertain how long the remis sions will last. Although hyperplastic polyps have traditionally been thought to be the most common gastric polyp, the frequency of fundic g land polyps has greatly increased, possibly due to the increased use o f proton-pump inhibitors, and now may be the most common of the gastri c polyps. Recent reports indicate that the frequency of gastroduodenal Crohn's disease may be higher than suggested by earlier literature. I n addition to the characteristic granulomas, focal gastritis, isolated giant cells, or a flat lesion in the duodenum may be seen. Most benig n gastric ulcers in developed countries are now due to NSAID use, whic h also may produce reactive gastropathy without H, pylori infection. G astric vascular ectasia is seen in a variety of conditions, but is mos t often idiopathic.