Reliability of rectal biopsy in distinguishing between chronic inflammatory bowel disease and acute self-limiting colitis

Aims : In order to assess the validity of previously proposed criteria for the differentiation of chronic inflammatory bowel disease (CIBD) from acute self-limiting colitis (ASLC) all rectal biopsies were reported by a single histopathologist with a long-term gastrointestinal interest over a 4.5-year period. Methods and results : The presence or absence of distorted crypt architecture, increased lymphocytes and plasma cells, villous mucosal architecture, granulomata, basal lymphoid aggregates, basal giant cells and Paneth cell metaplasia was noted for each biopsy. The definite presence of any of the above features, with the exception of intramucosal granulomata, was regarded as indicative of CIBD. Eighteen months later all available case notes were examined and the presenting clinical symptoms and working clinical diagnosis extracted. The final diagnosis, histopathological diagnosis and the presence or absence of any of the above histopathological features were correlated and the positive predictive value of each histopathological feature was calculated. A correct diagnosis of either CIBD or ASLC was made in 80 of 84 and 29 of 31 cases, respectively. Conclusions : Villous mucosal architecture and Paneth cell metaplasia were found to be specific features of CIBD. Distorted crypt architecture, basal lymphoid aggregates and plasma cell infiltration of the lamina propria were also useful features but strict definition of these features is required and discussed. Intramucosal epithelioid granulomas were identified in eight cases of CIBD and four cases of ASLC. In association with ruptured crypts intramucosal granulomas are not specific features of Crohn's colitis.