Ileocecal involvement in intestinal Behçet's disease and Crohn's disease: comparison of clinicopathological and immunophenotypic features.

Objectives: Intestinal Behçet's disease (BD) predominantly affects the ileocecal region and is currently diagnosed based on endoscopic features and clinical manifestations. It is difficult to distinguish between intestinal BD and Crohn's disease (CD) due to similar patient populations, gastrointestinal involvement, extraintestinal manifestations, and long-term recurrent course. In this study we aimed to compare the clinicopathological and immunophenotypic features of intestinal BD to CD.

Methods: The medical and pathological records of 29 cases of intestinal BD and 120 cases of CD diagnosed at Sir Run Run Shaw Hospital were retrospectively analyzed. Immunohistochemistry for CD3, CD20, FOXP3, myeloperoxidase, and quantitative analysis of the infiltrating inflammatory cells was conducted.

Results: Intestinal BD with ileocecal ulcer had a higher incidence of abdominal pain and a higher erythrocyte sedimentation rate than CD, while chronic diarrhea was more common in CD. Excessive neutrophils in the mucosal lamina propria, neutrophilic exudate on the ulcer surface, and prominent lymphocytic infiltration in ulcer tissues were statistically more frequent in intestinal BD than in CD. The numbers of FOXP3 T cells, CD3 T cells, and CD20 B cells in biopsy tissue from intestinal BD were significantly higher than CD, but the ratio of FOXP3 T cells to CD3 T cells was not statistically different.

Conclusion: Besides the typical clinical and endoscopic findings, diagnostic biopsies from the ileocecal region in intestinal BD show some histological and immunophenotypic features that are different from CD, which may be useful in distinguishing these two entities.