3.1 Duodenum ulcer. Mucosal glandular epithelium (white arrows) . Area of epithelial loss (black arrows) and formation of inflammatory granulation tissue (red arrows).
3.2 Area of tissue destruction (black arrows).
3.3 Inflammatory cells within granulation tissue. Cells with lobulated nuclei [ either eosinophils or neutrophils ( purple arrows for the latter)].
3.4 Ulcerated intestinal mucosa in Crohn’s disease. Area of pus accumulation ( black arrow ) and underlying formation of granulation tissue (red arrows).
3.5 Crohn’s disease. Transmural destruction (black arrow) , formation of new blood vessels (red arrows) within inflammatory granulation tissue.
3.6 The intestinal muscular layer (on the right) is interrupted by the inflammatory granulation tissue (red arrows) in Crohn’s disease.
3.7 Colon normal histology. Mucosa (white arrow) is formed by glandular cylindrical epithelium and lamina propria which normally contains a number of mononuclear immune cells (ie, lymphocytes). The muscularis mucosae seperates mucosa from submucosa (red arrow). A part of the muscular layer is observable (green arrows).
3.8 A closer look at normal colonic mucosa. Covering cylindrical epithelium (straight white arrows) and cylindrical glandular epithelium forming crypts (angular white arrows) with predominant presence of goblet cells (arrowheads). In normal glandular epithelium cells’ nuclei are basally orientated, close to the basement membrane ( oil-coloured arrows ).Also note the presence of a number of lymphocytes within the lamina propria (light blue arrows) and the muscularis mucosae ( yellow arrows).
3.9 Ulcerative colitis. Dense lymphocytic aggregates (light blue arrows) and destruction of colon mucosa (black arrow). Distorted crypts (angular white arrows) . Relative lack of inflammatory alterations in the submucosa (red arrow).
3.10 Ulcerative colitis. Inflammatory changes in bowel mucosa and presence of some atypical crypts (white angular arrow) with loss of goblet cells and nuclei pseudostratification. Consideration of dysplasia versus regenerative atypia due to inflammation.
3.11 Ulcerative colitis. Crypt destruction and formation of pus with numerous neutrophils (purple arrows).