Colonoscopy plus biopsy in the inflammatory bowel diseases.

Colon biopsies are critical in helping to diagnose diarrhea, to distinguish different forms of colitis, to determine the extent of disease, and to determine if neoplasia has arisen in the setting of chronic colitis. Table 3 summarizes the recommended locations and numbers of biopsies for different scenarios. Some of the technical aspects pertaining to those are also discussed elsewhere in this issue. Colon biopsies in some instances can be definitive, but this usually requires the appropriate clinical scenario. For instance, to appreciate that segmental granulomatous colitis is Crohn's disease and not the much rarer colonic sarcoidosis requires ancillary clinical information. Often colon biopsies may definitively reveal an abnormality, but the findings may be nonspecific in regards to a definitive diagnosis. To use colon biopsies most appropriately in patient management and to get the most mileage from them usually requires frequent clinician-pathologist interaction, often repeat endoscopy with [table: see text] biopsies at a different time, and the assessment of the biopsies in the clinical context.