Immunoglobulin G4-related constrictive pericarditis identified by cytological examination of pericardial effusion: a case report

BACKGROUND Immunoglobulin G4-related disease is increasingly recognized as a systemic autoimmune disorder characterized by immunoglobulin G4-positive lymphocyte infiltration. Organ biopsy and histopathology are the most important diagnostic methods; however, the significance of a cytological examination in immunoglobulin G4-related disease cases is still unclear. CASE PRESENTATION A 73-year-old Asian man who was a former tobacco smoker presented with progressive exertional dyspnea, systemic edema, and pericardial effusion. A cytological examination of his pericardial effusion detected three or four plasma cells per high-power field by Giemsa staining. Moreover, immunoglobulin G4-positive plasma cells were detected by immunostaining. Cardiac catheterization after pericardiocentesis revealed that both ventricular pressure traces showed an early diastolic dip and plateau. Positron-emission tomography with 18F-fluorodeoxyglucose imaging revealed inflammatory foci in his pericardium. A surgical pericardiectomy was performed and the resultant specimen showed significant immunoglobulin G4-positive plasma cell infiltration and marked fibrous thickening of his pericardium; therefore, a diagnosis of constrictive pericarditis due to immunoglobulin G4-related disease was made. Oral administration of 0.6-mg/kg/day prednisolone resolved his heart failure and he was discharged on foot 1 week later. CONCLUSION Our experience with this case indicates that cytological examination of pericardial effusion was useful in the diagnosis of immunoglobulin G4-related disease.