Multidisciplinary Management of Ruptured Mycotic Internal Iliac Aneurysm with Iliaco-Colonic Fistula: A Case Report

BACKGROUND Mycotic internal iliac artery aneurysms are exceptionally rare and life-threatening, especially when complicated by gastrointestinal fistulization and rupture. CASE REPORT This case report details the multidisciplinary management of an 84-year-old man presenting with a mycotic aneurysm of the left internal iliac artery that ruptured into the neo-sigmoid colon, resulting in severe gastrointestinal bleeding and hemorrhagic shock. Emergency management involved endovascular coil embolization and stent graft placement, stabilizing the patient hemodynamically. Definitive treatment was achieved through open surgical resection of the infected aneurysm and fistula, followed by vascular reconstruction using a bovine pericardial graft. Extensive intraoperative debridement minimized reinfection risk, and targeted antibiotic therapy was administered to control the polymicrobial infection. This case underscores the importance of individualized surgical strategies in managing complex vascular pathologies. The use of a bovine pericardial graft provided a durable reconstruction in an infected field, while collaboration between vascular and colorectal surgeons was critical to addressing the fistulization. The patient had a good recovery, with resolution of the infection and excellent graft function during follow-up. CONCLUSIONS This report highlights the challenges in managing ruptured mycotic aneurysms with gastrointestinal involvement and emphasizes the critical role of timely surgical intervention and an interdisciplinary approach for complex pathologies. Our findings support the integration of endovascular techniques for stabilization and open surgery for definitive treatment, demonstrating how a multidisciplinary approach can optimize outcomes in high-risk patients.