Chicken Bone Impaction Diagnosed by Computer Tomography Angiography: A Rare Cause of Lower Gastrointestinal Bleeding

A 71-year-old man presented with hematochezia and paraumbilical abdominal pain. The patient had a history of left hemicolectomy for unresectable large colonic polyps, but he had no prior episodes of gastrointestinal bleeding and was not on anticoagulants, antiplatelet therapy, or non-steroidal anti-inflammatory drugs. Upon arrival, the patient was hemodynamically stable with a normal complete blood count and international normalized ratio (INR). A computerized tomography angiogram (CTA) utilizing a “bleeding scan protocol” was performed. The radiologist identified a foreign body in the proximal sigmoid colon with adjacent inflammatory changes, with structural characteristics suggesting a chicken gracile bone (Figure 1). The radiologist felt that the location of the gracile bone was the likely source of gastrointestinal hemorrhage due to visible extravasation of contrast. The patient underwent colonoscopy, which demonstrated an impacted gracile bone not adjacent to any diverticula at 25 cm from the anal verge, which was removed via snare (Figure 2). No residual bleeding was detected on careful inspection of the colon after extraction of the bone. Although gracile bone impaction has been described in the past as a cause of upper gastrointestinal bleeding, only 1 case report described lower gastrointestinal bleeding from a chicken bone.1-4 Vosskamp et al described a case in which the patient underwent a hemicolectomy for lower gastrointestinal bleeding that showed a submucosal gracile bone adjacent to a bleeding diverticulum.4 Our case report exemplifies a rare etiology of lower gastrointestinal bleeding caused by acute gracile bone impaction in the sigmoid colon.