Treatment-Related Aortoenteric Fistula in a Patient With Intra-abdominal Cancer

Although aortoenteric fistula is traditionally associated with aortic aneurysms or grafts, modern multimodal oncologic therapies have introduced a new paradigm of aortic injury in native vessels. We describe a rare case of treatment-related aortoenteric fistula arising from a nonaneurysmal aorta in a 56-year-old woman with fallopian tube carcinoma. Her history included para-aortic lymph node excision, pelvic radiation, and recent bevacizumab therapy. Although these factors may act synergistically, bevacizumab represents a potential primary driver of vascular wall compromise. The patient presented with weakness and intermittent melena representing multiple herald bleeds but subsequently suffered a sudden inhospital cardiac arrest. Emergent computed tomography obtained prior to endoscopic evaluation revealed an aortoduodenal fistula despite a nonaneurysmal aorta, prompting successful endovascular aortic repair. This case illustrates that a nonaneurysmal caliber does not rule out aortoenteric fistula in patients with this specific risk profile. This report highlights one of the few documented cases of such vascular pathology following this specific combination of therapies. For unstable oncology patients with gastrointestinal bleeding and recent antiangiogenic therapy, emergency physicians should broaden the diagnostic workup to include early vascular imaging and enlist vascular specialists alongside standard endoscopic evaluation.