Autoamputation of a large pedunculated colon polyp.

A 49-year old man was referred for colonoscopy due to positive fecal occult blood test. Laboratory tests and physical examination were unrevealing. A large pedunculated polyp was found in the sigmoid colon (Figures 1A-1B). Due to inadequate bowel cleansing, polypectomy was not performed at that time. Upon repeat colonoscopy, 120 days later, bowel cleansing was excellent. The exam was performed by an expert endoscopist, achieving a good vision with a good colonic distension and without blind angulations. However, despite every effort, he was unable to find the polyp. A second expert endoscopist was asked to repeat the exam in the same session. Although he had reached the cecum twice, he couldn’t detect the polyp as well. Interestingly, both endoscopists described a prolapsed normal mucosa with a scar on its edge, in the site previously described as the polyp location (Figure 3). On close inspection, no adenomatous tissue was visible. We hypothesized a case of polyp autoamputation, with the prolapsed mucosa being the remnant of the stalk of the missing polyp. Indeed, the patient reported having suffered of a passage of bright red material and clots per rectum a few weeks before, without relevant consequences. To our knowledge only 3 cases of polyp autoamputation have been reported in the colon - ; autoamputation has been described also in the stomach and in the duodenum. It has been linked mainly with pedunculated type of polyps, which are subject to higher mechanical traction and torsion of the stalk. This is the first case documented with endoscopic images both before and after the event. Autoamputation can be either asymptomatic or accompanied by abdominal pain and bleeding, eventually leading to hospitalization.4 No fatalities have been reported. Intrinsic limitations of colonoscopy usually represent the first cause of missed polyps. Nevertheless, in case of pedunculated polyps that are not found anymore in subsequent colonoscopies, autoamputation is a possibility that gastroenterologists should take into account.