Giant colonic diverticulum presenting with painless rectal bleeding and diagnosed at angiography.

To cite: Andrade LC, Baptista M, Costa JF, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2014-204826 DESCRIPTION A 68-year-old man with a history of colonic diverticulosis presented with painless rectal bleeding. He was afebrile and haemodynamically stable. Mesenteric angiography was performed. The active bleeding was not identified, but a large airfilled lesion centrally located in the abdomen was seen. Its walls were vascularised by inferior mesenteric artery branches (figure 1). The scout view of an unenhanced abdominopelvic CT demonstrated a large, round, homogeneous radiolucent smoothly marginated lesion—balloon sign (figure 2A). Sagittal CT reconstructions (figure 2B) showed a 10×9 cm cystic mass communicating with the sigmoid colon and containing only gas. The diverticulum wall was thickened with surrounding fat stranding, indicating recent inflammation. The patient was treated conservatively with antibiotics. Considering the risk of future complications the patient is awaiting elective diverticulectomy. Giant colonic diverticulum, defined as a colonic diverticulum measuring 4 cm or more, represents an unusual manifestation of diverticular disease. 2 These diverticula are preferentially located in the sigmoid colon because of the increased frequency of diverticular disease in this location. 2 Other than through bleeding, giant diverticula can uncommonly present as intermittent masses or abscesses. Histologically, they can be true congenital diverticulum (wall composed of all structural layers), pseudodiverticulum (wall composed mainly of mucosa) or inflammatory diverticulum (wall composed of reactive scar tissue). 2 Clinically, patients can be asymptomatic or present with non-specific symptoms, such as intermittent unspecific abdominal pain, constipation with occasional diarrhoea, fever, nausea or melena. 2 The treatment gold-standard is surgery: diverticulectomy or segmental resection of adjoining colon and primary anastomosis whenever possible. 2 Figure 1 Mesenteric angiography demonstrated a large air-filled cystic structure centrally located in the abdomen (arrows) whose walls were vascularised by inferior mesenteric artery branches (square dot arrows). No active bleeding was identified.