ABSTRACT
Ulcerative colitis (UC) is an inflammatory disease primarily involving the colonic mucosa. The extension of classic UC is uniform and continuous with no intervening areas of normal mucosa. The rectum is usually involved and the inflammation extends proximally in a continuous fashion for a variable distance. However, as more patients get colonoscoped, it had been reported that there is a wide spectrum to what is called UC. There appear to be a few patients with otherwise typical UC but with rectal sparing. And also there are patients with classic distal UC who have an isolated area of cecal disease and segmental UC with skipped area. We have experienced a case of atypical UC initially presented as a isolated lesion around the appendiceal orifice with the segmental distribution of inflammatory change without an active inflammatory lesion in the rectum. It was considered that understanding of the significance of an isolated lesion in the appendix would contribute to the elucidation of the pathogenesis of UC.