Indeterminate colitis: definition, diagnosis, implications and a plea for nosological sanity

Abstract

In 1978, Price introduced the concept of indeterminate colitis to describe cases in which colonic resections had been undertaken for chronic inflammatory bowel disease (CIBD), but a definitive diagnosis of either of the classical types of CIBD, ulcerative colitis and Crohn's disease, was not possible. This was especially apposite in cases of acute fulminant disease of the colorectum. More recently, the term indeterminate colitis has been applied to biopsy material, when it has not been possible to differentiate between ulcerative colitis and Crohn's disease. In our opinion, and in those of other workers in this field, the term should be restricted to that originally suggested by Price. This then provides a relatively well-defined group of patients in whom the implications and management of the disease are becoming much clearer. Cases where there are only biopsies with CIBD, but equivocal features for ulcerative colitis and Crohn's disease, should be termed 'CIBD, unclassified', 'equivocal/non-specific CIBD' or IBD unclassified (IBDU), in line with recent recommendations. When the diagnosis is correctly restricted to colectomy specimens, there is now good evidence that the majority of cases will behave like ulcerative colitis. Furthermore, the diagnosis should not be a contraindication to subsequent pouch surgery. When the latter is undertaken, surgeons and patients can expect an increased complication rate, compared with classical ulcerative colitis, especially of pelvic sepsis, but most patients fare well. Only very occasional patients, around 10%, will eventually be shown to have Crohn's disease. This review describes the pathology of cases appropriately classified as indeterminate colitis and the implications of that diagnosis. It also highlights recent advances in its pathological features, clinical management and its immunological and genetic associations.

Inflammatory bowel disease unclassified

“…It is especially apposite in cases of acute fulminant disease of the colorectum (Martland and Shepherd, 2007). To avoid the indiscriminate use of IC/IBDU, and to conquer the diagnostic obstacles, a combination of clinical presentation, endoscopic appearance, radiology, histology, surgical findings, and even serologic testing is advocated.…”

Clinical Aspects of Idiopathic Inflammatory Bowel Disease: A Review for Pathologists

“…93 Several outcome studies suggested that most IC cases behave like UC. 88,91 Furthermore, the overall pouch failure rate in IC (20%) is closer to UC (10%) than to CD (30%-60%). Conversely, many presumed IC cases with severe pouch complications turn out to be CD.…”

“…Therefore, it is generally accepted that IC is probably UC; thus, patients with IC should not be denied a restorative procedure if there is no convincing evidence of CD. 17,88,91 A recent microRNA study of IC provided direct molecular evidence that the mRNA profile of IC clustered with that of UC. …”

“…When mucosal biopsies with overlapping features of UC and CD are encountered, a diagnosis of IBD, unclassified, or of equivocal/ nonspecific IBD is recommended. 91 Indeterminate colitis comprises about 5% to 10% of IBD, and the most common scenario is fulminant colitis with CD-like features in IBD that otherwise appears to be UC, with severe ulcer, superficial fissure, transmural inflammation, and rarely lymphoid aggregates underneath the ulcer, and relative rectal sparing.…”

The Role of Ultrasound in Intestinal Inflammatory Processes in Children and Adolescents

“…Based on clinical, radiological, endoscopic and histological characteristics, is classified as: Crohn's disease (CD), ulcerative colitis (UC) and Indeterminate Colitis (IC). The inclusion of this third category is the fact that 10% to 15% of patients did not have specific macro and microscopically well defined [1,2].…”