Unexpected presentation of post-implantation syndrome in a patient following aortoiliac aneurysm endovascular repair.

Surgery and endovascular repair remain the standard treatments for those at high risk of aneurysm rupture. Early detection and timely intervention, such as surgery or endovascular aortic repair (EVAR), are critical. EVAR is preferred due to its lower mortality compared to open surgery, but complications such as endoleaks, device migration, and post-implantation syndrome (PIS) are common. PIS affects 14% to 60% of EVAR patients, especially with polyester stent grafts. It typically presents with fever and elevated inflammatory markers, although other symptoms are less documented. An 84-year-old male with ischemic stroke, chronic coronary syndrome, and atrial fibrillation underwent stent graft placement for abdominal and iliac artery aneurysms. Discharged asymptomatic, he returned eight days later with fever, limb pain, and systemic inflammatory response syndrome. No infection or autoimmune disease was found through laboratory and imaging studies. Antibiotics failed, but magnetic resonance imaging of the limbs revealed edema in muscles, fascia, and subcutaneous tissues, indicating PIS. He improved rapidly with corticosteroids, confirming the diagnosis. This is the first case of PIS involving muscle, subcutaneous, and peri-vessel edema. It emphasizes the importance of recognizing atypical PIS presentations and using corticosteroids early to improve outcomes and avoid unnecessary investigations. Learning objective: Post-implantation syndrome (PIS) commonly presents with fever and elevated inflammatory markers after aortic endovascular repair. However, muscle, subcutaneous, and peri-vessel edema have not been previously linked to PIS in the literature. This case highlights the diagnostic challenge posed by this atypical presentation, with PIS diagnosed through exclusion. Notably, the patient responded positively to corticosteroid therapy, demonstrating its therapeutic value in managing the condition.