Angiodysplasia of the colon is the most common vascular lesion of the gastrointestinal (GI) tract and occurs when normal blood vessels undergo degenerative dilation leading to tortuous, thin-walled vessels that are prone to bleeding. Mucosal capillaries of the GI tract are the most commonly affected vessels. Occult GI blood loss due to angiodysplasia is most common in adults over age 60 and is rare in younger adults. Patients with aortic stenosis, heart failure with left ventricular assist devices, end-stage renal disease, or von Willebrand disease are predisposed to angiodysplasia formation.

Many patients with colonic angiodysplasia are asymptomatic as ectatic vessels are discovered on screening colonoscopy. The majority of colonic angiodysplasias are in the right colon, specifically involving the cecum, although they can be found anywhere from cecum to rectum.

Patients with symptomatic angiodysplasia present most often with chronic, occult blood loss (85% of cases), but patients can present with massive GI hemorrhage. The most common presenting symptoms are hematochezia, melena, Hemoccult positive stool, and iron-deficiency anemia.

Bleeding colonic angiodysplasias will often resolve spontaneously without endoscopic intervention, although they are amenable to endoscopic cauterization or clipping.

Related topic: GI bleeding