Inverted colonic diverticulum (ICD): report of two cases and literature review of a not that unusual endoscopic challenge

Inverted colonic diverticulum (ICD) is a rare intraluminal lesion occurring in about 0.7-1.7% of people, often endoscopically indistinguishable from polyps. Some unspecific endoscopic features may assist to distinguish polypoid ICD from true polyps. This differentiation bears relevance for the therapeutic approach, as colonic polyps require snare polypectomy, a practice which may be associated with colonic perforation in case of true ICD. The endoscopist, therefore, should be aware of the likelihood of detecting these lesions during colonoscopy. A close inspection and a gentle probing could assist in a correct diagnosis and avoid risky procedures such as biopsy or polypectomy. Rarely, a neoplasm arising over an ICD and its treatment has been described. We reported two cases, one of which with dysplasia, and their treatment, and reviewed all the ICD endoscopic cases so far reported in the literature, remarking the possibility of finding pedunculated ICDs or neoplasm arising over an ICD.