Macroscopic Endoscopy Findings in Microscopic Colitis

Microscopic colitis (MC) is a condition characterized by abnormal histology in the absence of endoscopic findings. However, case reports of endoscopic findings in MC have been published. We compared the prevalence of such findings in patients with MC and controls being evaluated for chronic diarrhea, as well as whether endoscopic findings are associated with MC severity.

Endoscopy images from patients in our institutional MC registry and controls presenting for colonoscopy for evaluation of chronic diarrhea without MC were reviewed by a panel of physicians for the presence of endoscopic findings: abnormal vascularity, mucosal tears, scarring, nodularity, and scalloping. In patients with MC, degree of clinical severity was compared between patients with and without endoscopic findings.

In our cohort of 275 patients, endoscopic findings were present in 41 of 168 (24.4%) of patients diagnosed with MC and 11 of 107 (10.3%) of those without MC (P-adj = .03). Scalloping (P-adj = .04) and abnormal vascularity (P-adj < .01) were associated with the diagnosis of MC; however, when cohorts were matched by risk factors for MC, this relationship was attenuated. There were no significant differences between endoscopic findings and MC subtypes (lymphocytic/collagenous colitis). Finally, no significant relationship was found between the presence of endoscopic findings and MC disease severity.

Our results suggest that subtle endoscopic findings are more common in patients with MC than those with other causes of chronic diarrhea. While findings are not unique to MC, clinicians should be aware of macroscopic findings seen in patients with MC.