ATYPICAL RECTOSIGMOID HISTOLOGY IN CHILDREN WITH NEWLY-DIAGNOSED ULCERATIVE-COLITIS

Background: In the untreated patient with inflammatory colitis, rectal sparing or patchy rectal inflammation is generally considered a sign of Crohn's disease initial, rather than ulcerative colitis (UC). Metho ds: The initial endoscopic rectosigmoid mucosal biopsies obtained at d isease onset from 12 untreated children with UC ultimately required su rgery were blindly reviewed (randomly mixed with another 62 specimens obtained from children with CD or treated UC). Biopsies were classifie d as typical UC if there was diffuse, active inflammation and severe c rypt destruction or distortion. Those with patchy, active inflammation and only mild crypt changes were classified as CD. Because all 12 sub jects had ultimately been proven to have UC by examination of a subtot al colectomy specimen, for the purposes of this report biopsies read a s either normal or CD were both considered evidence of atypical UC wit h rectal sparing. Results: Five of 12 subjects (seven biopsies) had at ypical histology. Mild, patchy inflammation was seen in six rectal or sigmoid biopsies, whereas one rectal biopsy was normal. The remaining seven subjects (10 biopsies) had diffuse inflammation. Two of five sub jects with atypical biopsies had an endoscopically normal rectosigmoid , one had patchy inflammation, and the remaining two had diffuse endos copic changes. All seven subjects with typical UC histology had diffus e endoscopic changes. Subjects with atypical findings could not be dif ferentiated by age, duration, or types of symptoms at presentation, ye ars of disease at colectomy, or indications for colectomy. Conclusions : Patchy or absent inflammation of the rectum and sigmoid can be prese nt in untreated children with UC at disease onset. Because such childr en may be mistakenly diagnosed as having CD, these data must be consid ered when treatments or clinical research protocols are designed to in clude children with colitis.