Immunoglobulin G4-related multiple systemic aneurysms and splenic aneurysm rupture during steroid therapy.

Immunoglobulin G4 (IgG4)-related disorders in various organs have recently been described, but multiple systemic aneurysms have not yet been reported. Here, we present a 68-year-old Japanese man with multiple systemic aneurysms and tumor-forming pericoronary arteritis who was undergoing low-dose corticosteroid therapy. Elevated serum IgG4 (2390 mg/dL) and IgG4-positive plasmacyte infiltration in the salivary glands led to a diagnosis of IgG4-related disease. High-dose corticosteroid therapy was initiated, whereupon the inflammatory lesions shrank. However, the large, well-developed common hepatic aneurysm and splenic aneurysm did not change. Our patient died of splenic aneurysm rupture in the sixth month of treatment. The autopsy revealed IgG4-positive plasmacyte infiltration in the coronary wall and a thinned splenic aneurysm wall. This case suggests that early high-dose corticosteroid therapy may be necessary for the treatment of IgG4-related cardiovascular disorders. A minor salivary gland biopsy might facilitate the early diagnosis of IgG4-related disease even if (18)F-fluorodeoxyglucose positron emission tomography provides no inflammatory findings.