Distinct colonoscopy findings of microscopic colitis: Not so microscopic after all?

Abstract

Microscopic colitis (MC) is considered an "umbrella term", comprising two subtypes, i.e., collagenous colitis (CC) and lymphocytic colitis (LC). They are classically associated with normal or unremarkable colonoscopy. In the last few years, reports have been published revealing findings that are thought to be characteristic or pathognomonic of MC, especially CC. A systematic electronic and manual search of PubMed and EMBASE (to December 2010), for publications on distinct endoscopic findings in MC, resulted in 42 relevant reports for inclusion in this review. Eighty eight patients with collagenous colitis were presented. Only one publication describing a distinct endoscopic pattern in LC was found. Typical findings in CC are alteration of the vascular mucosal pattern, mucosal nodularity, a sequence of change from mucosal defects to mucosal cicatricial lesions, and perhaps (although of doubtful relevance) mucosal pseudomembranes. A causal connection of mucosal defects with the use of lansoprazole seems to exist. Adoption of the proposed lesion description herein is recommended in order to improve homogeneity of future reports.

Macroscopic Findings in Microscopic Colitis: Two Case Reports and a Review of Literature

“…Despite being termed "microscopic" colitis, there have been a number of cases reporting distinct endoscopic findings in patients with collagenous colitis. Prevalence of mucosal tears as seen in our patients, are estimated to be around 1% based on prior reported studies [4]. However, the true number may be higher since not all of these cases are not reported.…”

“…As awareness and understanding of MC has improved over time, it's documented incidence and prevalence has increased. Although MC was initially conceived to be a histopathologic diagnosis, recent studies have shown specific endoscopic findings that can be associated with MC [4,5]. We report two cases of biopsy proven collagenous colitis that had macroscopic features on endoscopic examination.…”

Collagenous panenteritis: a rare cause of chronic diarrhoea

“…The advent of high-definition colonoscopes has led to discovery of distinctive endoscopic findings such as pseudomembranes, pruning of the mucosal vascular pattern and mucosal breaks in association with collagenous colitis 16 17…”

Biopsy interpretation of colonic biopsies when inflammatory bowel disease is excluded

“…Over the years, there have been an increasing number of reports of colonoscopic abnormalities associated with CC, calling into question its so-called microscopic nature. These include diminished vascular pattern, pruning of mucosal vasculature or crowded dilated tortuous capillaries; red spots, nodularity or textural abnormalities (with or without chromoendoscopy); hemorrhagic lacerations or linear tears more commonly in ascending and transverse colon (either spontaneously or with insufflation) and fine linear cicatricial lines or thick scar like ridges possibly due to healing of mucosal tears/ defects [86]. A mosaic or ''honeycomb'' pattern of the mucosa in the appropriate clinical context of chronic watery diarrhea has been reported by some as a distinguishing feature of CC [86,87].…”