IgG4-related disease can affect multiple organs. Involvement of the heart may include a periarteritis that can result in myocardial ischemia and/or sudden death.
Clinical features may include:
(1) chest pain
(2) acute myocardial ischemia with or without infarction
(3) sudden death
(4) inflammatory lesions in other organs
Abnormalities in the coronary arteries may be detected by angiography and intravascular ultrasound (IVUS). Inflammatory lesions may show uptake of 18FDG-PET.
Histopathologic findings:
(1) thickening of the adventitia
(2) infiltration of the adventitia and periarterial fat with lymphocytes and plasma cells
(3) > 40% of plasma cells stain for IgG4
(4) > 50 IgG4 positive plasma cells per high power field
Laboratory testing shows a significant serum IgG4 concentration.
Exclude other forms of immune vasculitis (giant cell arteritis, etc)
The inflammation usually responds to corticosteroids or immunosuppression.
