The Sydney System for classification of gastritis 20 years ago.

The roots of research into gastritis go back into the early decades of the 20th century. Modern aspects of its classification and knowledge of its biological course and consequences were relatively well known even at the time that Helicobcter pylori was discovered by Robin Warren and Barry Marshall in 1982. This discovery, however, significantly changed the field, establishing that the commonest form of gastritis is simply an infectious disease, a finding that raised enormous interest in the subject amongst gastroenterologists, microbiologists, pathologists and basic researchers. However, many of these "new" players in the field often had a limited knowledge of the morphological aspects of gastric inflammations and chronic gastritis. As a consequence in the late 1980's a Working Party was set up to review the biology and natural course of chronic gastritis, to propose a new classification for gastritis, and to provide simple guidelines for reporting the pathology of gastritis in endoscopic biopsies in an attempt to bring uniformity to the subject and facilitate comparative studies in what was to be an era of high research activity. These guidelines, The Sydney System: A New Classification of Gastritis was presented to the World Congress of Gastroenterology in Sydney in 1990, and was later published as six papers in the Journal of Gastroenterology and Hepatology. Now, twenty years on, this review looks back on the birth of Sydney System and why it is still important and successful.