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 18 Ffluorodeoxyglucose (FDG) uptake. A biopsy specimen of 18 F-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.

Immunoglobulin G4-Related Cardiovascular Diseases

“…[26][27][28][29][30][31] Matsumiya and colleagues detected IgG4-positive plasma cells in a biopsy specimen from a 50-year-old woman with a thickened pericardium. 26) Clinical fever symptoms and elevated serum IgG4 were promptly resolved by administration of a moderate-dose glucocorticoid.…”

Multiple nodules under the pericardium in a patient with IgG4-related disease

“…IgG4-RD is a multi-organ involved systemic disease and pericardial involvement mostly presents as pericarditis and pericardial thickening [2][3][4]. To our knowledge, pericardial nodules are unusual and there is no such report before.…”

IgG4-related Pericarditis in which Oral Corticosteroid Therapy Was Effective

“…As mentioned above, many patients with IgG4-RD and with IgG4-related pericarditis follow a chronic course, and most respond to steroid therapy (13, 20, 21). However, the patient's prognosis depends on the time between the initiation of the disease and the first visit or initial diagnosis, so some patients suffer a fatal outcome (13).…”

“…Surgical pericardiotomy to identify IgG4-positive cells in the pericardial specimen might have been useful; however, we did not perform pericardiotomy because the procedure requires general anesthesia, and there was a sufficient amount of pericardial fluid for a safe puncture in the present case (16). Although the usefulness of 18 F-fluorodeoxyglucose positron emission tomography/CT and 67 gallium single-photon emission CT have been indicated in terms of the sites and activities of inflammation and evaluating responses to steroid therapy, the findings of neither of these procedures are included in the current diagnostic criteria (13, 19, 20). The levels of IgG and IgG4 in pericardial fluid have not been described in the limited number of available reports; we therefore believe that the significance of this measurement remains unclear.…”