Polypoid prolapsing mucosal folds with diverticulosis and colonic muco-submucosal elongated polyps

Background:  In 1991, Kelly first reported the presence of red or brown mucosal protrusions or polyps associated with diverticular disease and described this syndrome as ‘polypoid prolapsing mucosal folds in diverticular disease.’ In 1994, Matake et al. independently reported several long mucosal intraluminal protrusions as ‘colonic muco-submucosal elongated polyps.’ The purpose of the present study is to address the relationship between the two syndromes. Methods:  We performed a careful review of the published work on the clinicopathological features of these syndromes. Results:  The clinical symptoms associated with these two syndromes do not differ notably. Because of the mucosal redundancy of the colonic mucosa, the excessive propulsive power of peristalsis may play an important role in generating both types of polyps. Neither ‘polypoid prolapsing mucosal folds in diverticular disease’ nor ‘colonic muco-submucosal elongated polyps’ fit into any of the conventional classifications, and their histological characteristics are similar. In addition, we describe the diagnosis and clinical management at our institution of an emergent case of polypoid prolapsing mucosal folds in diverticular disease. Conclusion:  In light of their similar etiology and pathology, we propose that these conditions are different manifestations of the same entity. Unifying these two classifications into one makes the diagnosis of either type of polyp less onerous for clinicians, endoscopists and pathologists. As a consequence, it is likely that more cases will be diagnosed and reported. The accumulation of more cases will lead to deeper understanding and further clinicopathological characterization of diverticular polyps.