Clinical significance of pathologic abnormalities in biopsy samples from the appendiceal orifice

Aims: Appendiceal orifice mucosa often appears inflamed endoscopically, even when other colonic segments appear normal. Histological findings in biopsy samples taken from endoscopically abnormal mucosa may simulate a variety of inflammatory colitides. We performed this study to evaluate the clinical implications of inflammatory changes isolated to the appendiceal orifice. Methods and results: In this double cohort study, biopsy samples from 26 histologically abnormal appendiceal orifices were reviewed. Twenty-five control cases were culled from endoscopically normal (n = 11) and abnormal (n = 14) appendiceal orifices that were histologically normal. Histological findings were correlated with presentation, medication history, findings at other colonic sites and clinical outcomes. Study cases displayed active inflammation (n = 12), chronic active inflammation (n = 13) or features simulating collagenous colitis (n = 1). Eighteen patients had biopsies taken from other colonic sites; these revealed benign polyps (n = 10) or displayed active (n = 4) or chronic active (n = 4) inflammation. All patients with findings isolated to the appendiceal orifice were asymptomatic at most recent clinical follow-up. Four of eight (50%) of the patients with inflammation in other biopsy samples were ultimately diagnosed with ulcerative colitis, in keeping with the well-established role of the appendix as a ‘skip lesion’ in that disorder. Control patients presented for screening colonoscopy (n = 19), iron deficiency anaemia (n = 3) or change in bowel habits (n = 3) and none reported gastrointestinal symptoms upon follow-up, regardless of the endoscopic appearance of the appendiceal orifice. Conclusion: Isolated inflammation of the appendiceal orifice mucosa should not be regarded as a feature of evolving inflammatory bowel disease or other types of chronic colitis.