A case of colonic muco-submucosal elongated polyp (CMSEP) misdiagnosed as a inverted colonic diverticulum (ICD).

ABSTRACT

CMSEP is a large intestine polyp with a long and broad stalk and a "worm-like" appearance which is covered by normal mucosa. The submucosal layer consists of edematous and fibrotic interstitium, adipose tissue, dilated blood vessels, and lymphatic follicles[1]. Endoscopic magnification of the mucosal surface showed a uniform honeycomb pattern of regular blood vessels, with soft and deformable "folds" and "gyrus" at the top. The exact pathogenesis of CMSEP is still unclear.