Histopathologic Manifestations of Crohn Disease in Duodenal Endoscopy Biopsy: The Value of Different Patterns of Involvement of Brunner Glands

Crohn disease (CD) not uncommonly involves the upper gastrointestinal tract, usually gastric antrum and proximal duodenum. The most consistent histopathologic manifestations of CD in duodenal biopsies are mucosal erosion, focal active inflammation, and granulomas. Since CD is a transmural inflammation and since duodenal biopsy may include submucosal Brunner glands, we aimed to find if CD has any specific histopathologic manifestations in Brunner gland lobules and their ducts compared to other duodenal inflammatory lesions. We carried out a retrospective review study over 6 years retrieving duodenal biopsy specimens in CD patients. We compared duodenal specimens involved by CD with other inflammatory lesions, for example, ulcerative colitis (UC), Helicobacter pylori-associated gastritis, non-Helicobacter gastritis, Celiac sprue, infections, and drugs. We found focal active duodenitis and erosion in CD cases and non-CD cases. Granulomas were found in CD cases. Five cases of CD showed inflammatory and degenerative changes of Brunner glands. Focal patchy active inflammation of only portion of submucosal Brunner gland lobule, mucosal Brunner glands, and their ducts was solely found in CD cases. This focally enhanced inflammation of Brunner glands was not found in other lesions. Whether this phenomenon of focal active “lobulitis” and “ductitis” is a specific sign of duodenal CD compared to UC and other inflammatory lesions warrants verification. We encourage endoscopists to include submucosal Brunner lobules in their duodenal biopsy samples and pathologists to look for these patterns of involvement particularly in patients suspected of CD.