Polypectomy for Colonic Arteriovenous Malformation

Abstract

A 59-year-old Caucasian female with a past medical history of hypertension presented for a routine screening colonoscopy. The patient denied any symptoms of melena, hematochezia, fatigue, shortness of breath, or palpitations. Significant medications included Aspirin 81 mg once per day. Her hemoglobin was stable at 13.5 g/dL and platelet count was 256 x 103 platelets/mL. Colonoscopy revealed a 7 cm elongated polyp-like lesion with a narrow slit-like opening in the descending colon, 50 cm from anal verge (figure 1). There was initial concern for an inverted diverticulum but was thought to be unusually long. Mucosal biopsy showed normal colonic mucosa. In view of unexplained etiology of the structure and polypoidal appearance, colonoscopy was repeated with an intention of performing polypectomy to rule out an underlying adenoma. During colonoscopy an endoloop was deployed at the base of the elongated polypoidal structure and a hot snare polypectomy was performed excising the lesion. Three endoclips were placed at the base of the lesion to prevent post-polypectomy bleeding (figure 2). Adjacent colon was tattooed with endospot just proximal to the polypectomy site. The histological examination of the specimen revealed it to be a polyp-like colonic arteriovenous malformation (AVM). A colonoscopy was subsequently repeated after 6 month and the post polypectomy site identified by the tattoo placement showed no gross abnormality. Colonic AVMs are a very common cause of lower gastrointestinal bleeding. They are most commonly found in the right colon with a typical gross appearance of flat, bright red submucosal blood vessels that have an ectatic and/or tortuous characteristic. A pedunculated polypoid appearance of these lesions in the colon isextremely rare and has scarcely been reported in the literature. We present this case to increase awareness amongst Gastroenterologists regarding polypoidal variant of colonic AVM and successful endoscopic management adopting measures to prevent post- polypectomy bleeding.1629_A Figure 1 No Caption available.1629_B Figure 2 No Caption available.