Inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), are chronic, idiopathic diseases characterized by the inflamation of the wall tube (1). Ulcerative colitis was first described in the mid-1800s (2), whereas Crohn's disease was first reported later, in 1932, as "regional ileitis" (3). Because Crohn's disease can involve the colon and shares clinical manifestations with ulcerative colitis, these entities have often been conflated and diagnosed as inflammatory bowel disease, although they are clearly distinct physiopathological entities. Ulcerative colitis is the most common form of inflammatory bowel disease worldwide. In contrast to Crohn's disease that can extend in the entire intestinal wall, ulcerative colitis is a disease of the mucosa that is less prone to complications and can be cured by means of colectomy, and in many patients, its course is mild (4).
Until recently, it was considered that, unlike Crohn's disease (whose location can be at any level of the digestive tract), ulcerative colitis is strictly localized in the colon. However, in the recent years, increasingly more studies reveal the existence of a moderate, chronic, diffuse gastroduodenitis in pacient with ulcerative colitis, which normally causes no macroscopical lesions being highlighted only based on histopathologic examination (5). Most of these studies invoke the presence in the duodenum of a diffuse inflamation with neutrophilic infiltration in the glandular crypts, with redness and swelling during an acute exacerbation. In the stomach the predominant lesions are chronic focal gastritis (5,6,7).