Identification and endovascular treatment of a rare deep circumflex iliac artery-L3 lumbar artery anastomosis causing type II aortic aneurysm endoleak.

Type II endoleaks are the most common complication after endovascular aneurysm repair typically arising from mesenteric and lumbar inflow vessels, whereas alternative collateral sources are less frequently recognized. We report a case of a deep circumflex iliac artery-mediated collateral causing persistent sac perfusion, identified on preprocedural imaging and confirmed angiographically. Targeted coil embolization resulted in occlusion of the culprit pathway with resolution of sac opacification. Follow-up imaging demonstrated a separate endoleak from a distinct collateral source without sac enlargement, consistent with flow redistribution. These findings highlight the importance of evaluating atypical collateral pathways.