DIFFERENTIAL DIAGNOSIS OF INTESTINAL BEHCET'S DISEASE and CROHN'S DISEASE BY COLONOSCOPIC FINDINGS

Both Crohn's disease and intestinal Behcet's disease can cause nonspecific ulcerative lesion in any part of the intestine. The differential diagnosis between these two diseases is often difficult due to lack of pathognomic findings. The aims of this study were to investigate the colonoscopic findings and to find valuable parameters in differentiation between Crohn's disease and Behcet's disease. Methods  From August 1989 to June 2000, 183 patients were diagnosed as Crohn's disease (82) or intestinal Behcet's disease (101). We evaluated endoscopic features of 170 patients (100 patients with Intestinal Behcet's disease and 70 patients with Crohn's disease) who had ulcerative lesions on colonoscopy. Classification and regression tree method was used for the differentiation of two diseases by colonoscopic findings. Results  The distribution of lesions was divided into 3 types; focal (single or multiple), segmental, and diffuse. Most (93%) of the lesions in intestinal Behcet's disease distributed focally, in contrast many (70%) of the lesions in Crohn's disease showed segmental or diffuse distribution. The shape of ulcer was commonly round/oval (68%) or irregular (24%) in intestinal Behcet's disease while longitudinal (49%) or irregular (30%) in Crohn's disease. The ulcer in intestinal Behcet's disease tended to deeper, and more discrete than that in Crohn's disease. Stricture, inflammatory polyp, and perianal lesion were more common in Crohn's disease. Statistically these characteristics could make a tree structured classification rule as follows (Hit ratio: 91.9%). Round/oval  Intestinal Behcet's disease Ulcer Irregular Focal distribution Intestinal Behcet's disease Segmental or diffuse distribution Crohn's disease Longitudinal  Crohn's disease Conclusion  The shape of ulcer and distribution of lesions were the two most distinguishable endoscopic features. Round/oval ulcer was the characteristics in intestinal Behcet's disease, and longitudinal ulcer was that in Crohn's disease. When the ulcer was irregular, focal distribution suggested intestinal Behcet's disease, while segmental or diffuse distribution suggested Crohn's disease.