A 75-year-old man underwent endovascular repair of the abdominal aortic aneurysm. The procedure was aorto-uni-femoral endograft and femorofemoral crossover bypass using PTFE graft. The postoperative course was satisfactory, but 4 years after operation, he was admitted complaining of abdominal fullness. CT scan showed significant increase of aneurysm diameter to 13cm without evidence of endoleak. Endograft replacement with a new Dacron graft was carried out. Intraoperative findings suggested perigraft seroma related to the use of PTFE, and there was no endoleak. The postoperative course was uneventful. Pathological finding of aneurysm showed a lack of hemocytes and thrombocytes.