Old and New Diagnostic Paths in Inflammatory Bowel Diseases

In the setting of the inflammatory bowel diseases, the role played by pathologists in the histological assessment of mucosal biopsy can be ideally divided into four steps. As a sequential proceeding, the histological evaluation has to deal with (1) the identification of the intestinal inflammation as consistent with ulcerative colitis or Crohn’s disease, distinguishing them from their own mimickers; (2) the assessment of the inflammatory activity, thus highlighting their main descriptors, also including grade and distribution; (3) the evaluation of the histological features suggesting treatment response; (4) the histological detection of dysplasia and other complications in long-standing diseases. Requirements that should support the biopsy interpretation include (1) the thorough endoscopic data from the colonoscopy; (2) a comprehensive mucosal mapping; (3) a proper methodological approach to the mucosal specimens during the pre-analytical phase; (4) the methodological approach to the histological evaluation. In the last few years, efforts have been undertaken to identify novel histological markers of mucosal dysfunction in inflammatory bowel disease, which could help to identify novel markers of mucosal healing.