title: Diversion colitis in children: an iatrogenic appendix vermiformis?
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Pathology, University of Wales College of Medicine, Cardiff, UK. vujanic@cf.ac.uk
authors.forename: G M
authors.initials: GM
authors.lastname: Vujanić
authors.forename: S D
authors.initials: SD
authors.lastname: Dojcinov
mesh_terms: D001065:Appendix / Q000473:pathology*; D002675:Child, Preschool; D003092:Colitis / Q000209:etiology / Q000473:pathology*; D003093:Colitis, Ulcerative / Q000175:diagnosis; D003106:Colon / Q000473:pathology / Q000601:surgery; D003125:Colostomy / Q000009:adverse effects; D003937:Diagnosis, Differential; D005260:Female; D006627:Hirschsprung Disease / Q000150:complications / Q000601:surgery; D006801:Humans; D007049:Iatrogenic Disease; D007081:Ileostomy / Q000009:adverse effects; D007223:Infant; D008297:Male