Aims: Diversion colitis (DC) is a localized, relatively benign, iatrogenic condition which occurs in almost 100% of diverted colonic segments in patients who undergo ileostomy/colostomy for various reasons. The aim of this study was to establish histological features of DC in children.
Methods and results: Twenty-three cases of DC following colostomy for Hirschsprung's disease in young children were analysed. The distinguishing features included prominent follicular lymphoid hyperplasia (100%), chronic mucosal inflammation (100%), accompanied by a variable degree of acute inflammation (78%) and Paneth cell metaplasia (26%). Less frequent histological findings were as follows: mild goblet cell depletion (22%), foci of cryptitis (13%), crypt abscesses (13%) and mild architectural distortion (22%). A previously unrecognized feature was the presence of mucosal aggregates of eosinophils, found in 43% of cases. A striking similarity between the normal appearance of the vermiform appendix and pathological features in DC was noted and the possible relationship between the two is discussed.
Conclusions: Histological features of DC in children are very similar to those described in adults. They should help to distinguish it from ulcerative colitis and Hirschsprung's-associated enterocolitis in order to prevent inappropriate therapy and follow-up. There are many similarities between DC and the normal appendix vermiformis.