A case of multiple immunoglobulin G4-related periarteritis: a tumorous lesion of the coronary artery and abdominal aortic aneurysm.

Immunoglobulin G4 (IgG4)-related disease can occur in various organs, most of which are glandular or ductal tissues. Here, we report a case of multiple IgG4-related vascular lesions. A 63-year-old patient was found to have an abdominal aortic aneurysm and a tumorous lesion around the right coronary artery. The surgically resected aneurysmal wall and a tumorous lesion of the right coronary artery showed similar histologic features including diffuse lymphoplasmacytic infiltration, occasional eosinophils, and obliterative phlebitis. Immunohistochemically, numerous IgG4-positive plasma cells were evident within the lesions. The serum concentrations of IgG4 in the preoperative period was 456 mg/dL (reference range, <135), which decreased to 242 mg/dL 2 weeks after surgery. We made a diagnosis of multiple IgG4-related periarteritis manifesting as an abdominal aortic aneurysm and a tumorous nodule of the coronary artery. This case report suggested that IgG4-related disease can occur in the vascular system and manifest as an aneurysm or a periarterial mass lesion.