Exacerbation of immunoglobulin G4-related inflammatory abdominal aortic aneurysm after endovascular repair.

A 78-year-old male was admitted to our hospital with lumbar pain and was found to have an abdominal aortic aneurysm (AAA) and femoral artery aneurysm (FAA). Initially, the patient underwent endovascular aneurysm repair (EVAR) for the AAA and aneurysmectomy for the FAA. The FAA was diagnosed by histology as immunoglobulin G4-related disease (IgG4-RD). The preoperative serum IgG4 level was within the normal range, although a slight serum interleukin-6 (IL-6) elevation was observed. Four years later, the AAA-sac diameter had expanded and the serum levels of both IgG4 and IL-6 levels had increased. Six years after the initial EVAR, aneurysmorrhaphy of AAA-sac was performed. The resected specimen revealed adventitial fibrosis and prominent lymphoplasmacytic infiltrate with regulatory T cells, satisfying histological diagnostic criteria for IgG4-RD. Immunoreactive matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9, and IL-6 were detected within numerous spindle cells in the adventitia of both the FAA and the AAA-sac. Five months after the aneurysmorrhaphy, the residual AAA-sac was again enlarged with a thickened wall that accumulated [18 F] fluoro-2-deoxy-D-glucose (FDG-PET) on positron emission tomography; these findings were paralleled by increased levels of serum IgG4 and IL-6. Therefore, persistent inflammation after EVAR may be attributed to the inflammatory sequelae of IgG4-RD.