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

Microscopic colitis (MC) is emerging as an increasingly common cause of chronic and debilitating watery diarrhea in the adult population. The term microscopic colitis was first coined by Park et al in 1980 as an entity causing persistent watery diarrhea [1]. It was initially characterized by chronic watery diarrhea and normal endoscopic findings with abnormal histopathology on biopsy [2]. Microscopic colitis comprises two subtypes with lymphocytic colitis and collagenous colitis, based on differing microscopic findings. Lymphocytic colitis is characteristically associated with more than 20 intraepithelial lymphocytes per 100 surface epithelial cells [3]. Collagenous colitis is characterized by a thick subepithelial collagen band (more than 10μm) in the basal membrane [3]. 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.