Reporting Colonic Biopsies in Patients With Inflammatory Bowel Disease; a Practical Approach

Crohn's disease (CD) and ulcerative colitis (UC) are common diseases; for convenience, we lump them together as inflammatory bowel disease (IBD). Colonic biopsies are essential for establishing a diagnosis, monitoring treatment, and/or identifying complications. This article attempts to detail the histological criteria of UC and CD and also informs on a lifelong approach of reporting colonic biopsies from patients with IBD. Often the clinical information on the accompanying request form is not available to the pathologist. In these cases, the author has initiated a reproducible system of pattern-based reporting with a differential diagnosis. This type of report offers a working diagnosis for the clinician before the final diagnosis, which is recommended to be undertaken in a setting of combined clinico-pathological conference (CPC). This system carries objective parameters and standardizes reporting to significantly minimize the interobserver variations among reporting pathologists. If a CPC facility is not available, we offer an alternative evidence-based arrangement. We discourage the use the term "nonspecific colitis" as we have shown that it has no clinical value or agreed-upon and recognized histopathological features. As the paper addresses mucosal biopsies, the entity of indeterminate colitis will not be included in this article as this diagnosis is strictly based on colonic resectate.