A clinicopathologic study of immunoglobulin G4-related disease of the femoral and popliteal arteries in the spectrum of immunoglobulin G4-related periarteritis

Background Immunoglobulin (Ig) G4-related disease has recently been recognized to occur in the cardiovascular system in the aorta and main branching arteries, often manifesting as aneurysms and arteritis/periarteritis. Peripheral arteries (the femoral and popliteal arteries) are frequent sites of arteriosclerosis obliterans (ASO) and occasionally show aneurysms or arteritis. This study re-examined peripheral arterial lesions from the standpoint of IgG4-related disease. Methods The study comprised 104 patients who underwent surgical treatment of peripheral arterial lesions, including 30 patients with peripheral arterial aneurysms (PAAs) and 74 with ASO. IgG4-related disease was identified on the basis of diffuse infiltration of numerous IgG4-positive plasmacytes as revealed by immunohistochemical examination. Clinicopathologic features were compared between IgG4-related and IgG4-unrelated lesions. Results IgG4-related disease was found in four of the 30 patients with PAAs (13.3%; two in the deep femoral artery, two in the popliteal artery) but not in any patients with ASO. IgG4-related PAA displayed clinicopathologic features resembling those of other IgG4-related diseases and a characteristic saccular appearance ( P = .002). Conclusions IgG4-related disease was detected in PAA patients but not in ASO patients. IgG4-related disease thus represents one potential etiology of aneurysm in the peripheral arteries.