title: Indeterminate colitis.
abstract: Indeterminate colitis (IC) originally referred to those 10-15% of cases of inflammatory bowel disease (IBD) in which there was difficulty distinguishing between ulcerative colitis (UC) and Crohn's disease (CD) in the colectomy specimen. However, IC is increasingly used when a definitive diagnosis of UC or CD cannot be made at colonoscopy, in colonic biopsies or at colectomy. The diagnostic difficulties may explain the variably reported prevalence of IC. Clinically, most patients with IC evolve to a definite diagnosis of UC or CD on follow up. The role of ancillary tests in the distinction of UC from CD is reviewed. The low sensitivity of serological markers limits their usefulness. Other tests include upper endoscopy and magnetic resonance imaging. The definition of IC may not be a purely histological one derived from resected specimens, but rather a clinicopathological one. This review offers some personal observations and viewpoints, and proposes an approach to some of the relatively more esoteric combinations of findings.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, and Department of Pathology, University Health Network, Toronto, Ontario, Canada, M5G 2C4. maha.guindi@uhn.on.ca
authors.forename: M
authors.initials: M
authors.lastname: Guindi
authors.forename: R H
authors.initials: RH
authors.lastname: Riddell
mesh_terms: D003082:Colectomy / Q000379:methods; D003092:Colitis / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D003093:Colitis, Ulcerative / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D003106:Colon / Q000473:pathology; D003424:Crohn Disease / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012002:Rectal Diseases / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D012007:Rectum / Q000473:pathology; D009626:Terminology as Topic