Immunoglobulin4 (IgG4)-related disease is a systemic inflammatory disease characterized by elevation of serum
IgG4. It involves various organs such as the pancreas (
autoimmune pancreatitis), lacrimal gland (
Mikulicz's disease), retroperitoneum (
retroperitoneal fibrosis), aorta (
aortic aneurysm and
aortitis), heart (
constrictive pericarditis), and pseudotumors around the coronary arteries. These disorders often coexist in accordance with progression of the disease. Because IgG4-related cardiovascular disorder affects the patient's prognosis, early detection and treatment is important. Coronary CT imaging and echocardiography accidentally detect IgG4-related disorders and (18)FDG-PET imaging can identify active
inflammation in the lesions. Measurement of serum
IgG4 levels and tissue biopsy are necessary for diagnosis. Minor salivary gland biopsy is recommended even though (18)FDG uptake is not detected when it is difficult to obtain a biopsy specimen from IgG4-related cardiovascular lesions. The first-line treatment is high-dose
corticosteroid therapy, however, relapse is often reported.
Corticosteroids suppress the development of active inflammatory diseases such as
aortitis,
pericarditis, and pseudotumors, but already-developed lesions do not respond. A large developed
aneurysm can
rupture even during or after
corticosteroid therapy, therefore, additional surgical treatment may be needed. Treatment of IgG4-related cardiovascular disorders might require higher doses of
corticosteroids than IgG4-related extracardiovascular disorders. The adequate dose of
corticosteroid, type and dose of
immunosuppressant, and surgical intervention should be carefully considered on a case-by-case basis.