Endoscopic biopsies

• Crohn’s disease
• ulcerative colitis
• colitis
• diagnostic reproducibility
• inflammatory bowel diseases

Endoscopic biopsies from the gastrointestinal tract form a large proportion of the specimens that are analysed in pathology units, and at present inflammatory lesions outnumber neoplastic diseases in endoscopic biopsy material. A large bulk of evidence supports the use of colonoscopic biopsies as an essential step in the diagnostic work up of inflammatory bowel diseases. Because no single pathognomonic lesion has been identified to date for the most common forms of colitis, the diagnosis usually derives from a complex evaluation of multiple elementary lesions and their topographical distribution. Few studies have analysed in detail the reliability and/or reproducibility of the histological changes that are used to distinguish inflammatory bowel disease from other forms of colitis, and Crohn’s disease (CD) from ulcerative colitis (UC).^1–4

The paper by Bentley and colleagues⁵ in this journal (http://jcp.bmjjournals.com/cgi/content/full/55/12/955) represents a noteworthy effort towards a better understanding of the diagnostic reliability of the elementary lesions currently used to diagnose colitis. It explores the basis of pathological disagreement and leads to some conclusions that we might expect and others that we would not. The conclusions may be summarised as follows:

• Full colonoscopy biopsies provide more accurate diagnoses than rectal biopsies, especially for CD.

• The overall diagnostic accuracy of endoscopic biopsies is, in any case, lower in CD than in UC.

• The discussion of diagnostic criteria and guidelines among pathologists improves the diagnostic accuracy, especially in CD.

• Expert gastrointestinal (GI) pathologists are not able to provide more accurate diagnoses than non-experts.

Among the expected findings, this workshop based approach …