集簇性“mucosal bridge”を示した潰瘍性大腸炎の1症例

A Case of Ulcerative Colitis Showing Clusters of Mucosal Bridges

　大腸に潰瘍を形成する疾患は数多くあり¹⁾²⁾潰瘍性大腸炎との鑑別診断は困難な場合が多い．潰瘍性大腸炎の病型分類の1つに，病変の拡がりによる分類があり，定型的潰瘍性大腸炎（classical ulcerative colitis）と，いわゆる右側結腸炎（right-sided colitis），区域性結腸炎（segmental colitis）とに大別される．前者は直腸，S字状結腸に始まり上行性に進展していくものといわれており，後者は右側結腸に始まり，下行性に進展していくものといわれている．

　潰瘍性病変が右側結腸のみに認められる場合には，腸の炎症性疾患の中でもとくに潰瘍性大腸炎の1病型である右側結腸炎と，肉芽腫性大腸炎（granulomatous colitis），大腸Crohn病（Crohn's disease of the colon）との鑑別診断がしばしば問題となる．潰瘍性大腸炎のX線所見，内視鏡所見および生検，組織学的所見に関しての多くの報告はあるが，pathognomonicな所見はないとされている．

　The patient is a 43-year-old man with a chief complaint of bloody stool. Barium enema and endoscopic examination of the colon revealed a great number of inflammatory polyps, mucosal tags and mucosal bridges, projecting over the intestinal lumen, that were seen only on the right-hand side of the colon. The rectum, sigmoid and the small intestine were free from any remarkable change and we arrived at a diagnosis of ulcerative colitis. The resected specimen did not show any evident erosions or ulcerations on the mucosal surface, but clusters of mucosal bridges, covered diffusely with slender protrusions, were observed only on the right-hand side of the colon. The whole picture was bizarre, looking as if round worms had swarmed there. There was no noticiable alteration in the serosa.

　Inflammatory polyposis of the colon is seen in other intestinal inflammatory intestinal diseases, but clusters of mucosal tags and brigdes are believed to be findings characteristic of ulcerative colitis. Histological investigation how the muscularis mucosae was located within the mucosal bridges showed us that undermining ulcer played an important role in the development of mucosal bridging.