Endoscopic Recognition of Giant Colonic Diverticula

Abstract

Introduction: Giant Colonic Diverticulum (GCD) is a rare endoscopic finding which is typically diagnosed radiologically during evaluation of abdominal pain or abdominal mass felt on exam. We present a case of GCD initially identified on colonoscopy, which was performed for iron deficiency anemia without prior abdominal imaging. Case: An 82-year-old male with a history of diverticulosis was admitted after being found down from a mechanical fall. On admission his hemoglobin was 6.9 mg/dL, which was decreased from 14.6 mg/dL eight months prior. He denied any overt gastrointestinal bleeding, but given the severity of his anemia, iron deficiency, and lack of other etiology for blood loss he underwent esophagogastroduodenoscopy and colonoscopy. Colonoscopy revealed several large diverticula, the largest of which had an approximate 3 cm os and surrounding erythematous and friable mucosa that was biopsied showing ulcer debris and evidence of diverticular colitis (Figure 1, 2). The next day a CT scan of the abdomen revealed a large 7 cm gas-filled cyst in apparent communication with the sigmoid colon (Figure 3). Eight days later he developed worsening abdominal pain and a repeat CT scan showed a rim-enhancing collection of fecal material and air in the location of the prior gas-filled cyst along with moderate pneumoperitoneum. He then underwent exploratory laparotomy with sigmoid colectomy and was found to have a thin walled large diverticula with an identified perforation. Discussion: Giant colonic diverticula are greater than 4 cm in size and 90% are found in the sigmoid colon. Pathogenesis of these lesions is incompletely understood, but one theory is that they are secondary to subserosal perforation which then forms a walled off abscess cavity in communication with the lumen of the colon. Though they are typically identified on abdominal imaging they may be encountered initially during colonoscopy as in our case. Care should be taken to avoid perforation in these cases given there is only a thin wall of fibrotic tissue without normal intestinal layers in 66% of cases.Figure: Sigmoid colon with large mouth diverticula, with heaped up friable surrounding mucosa.Figure: Image within the giant diverticulum demonstrating gross amounts of exudate and granulation tissue.Figure: CT scan with giant colonic diverticulum in communication with sigmoid colon.