Elevated serum IgG4 complicated by pericardial involvement with a patchy 18F-FDG uptake in PET/CT: Atypical presentation of IgG4-related disease

Abstract

IgG4-related pericardial involvement has rarely been reported and its clinical features remain unknown. We herein report a case of a 50-year-old woman with pericarditis who presented with a fever, elevated C-reactive protein levels, elevated serum IgG4 concentrations, and thickened pericardium with a patchy 18F-fluorodeoxyglucose (FDG) uptake. A biopsy specimen of 18F-FDG accumulated in the mediastinal lymph nodes revealed an abundant infiltration of IgG4-bearing plasma cells without fibrosis. Moderate-dose glucocorticoids promptly resolved the physical, serological, and imaging abnormalities, thus indicating a relatively acute and reversible nature of IgG4-related pericardial involvement.