A very rare phenotype of immunoglobulin G4-related disease that was manifested as constrictive pericarditis: a case...

Constrictive pericarditis (CP) can arise from various causes, including post-operative degeneration, tuberculosis, and sequelae of pericarditis. Immunoglobulin (Ig) G4-related disease is a rare but recognized cause of CP. However, the specific mechanisms underlying these aetiologies and pathologies remain unclear.

A 67-year-old man presented with a 6-month history of bilateral leg oedema, anorexia, and dyspnoea on exertion. Computed tomography (CT) revealed significant pericardial thickening without calcification, right pleural effusion, and ascites. Echocardiography demonstrated a reduced left ventricular ejection fraction and pericardial thickening. The early diastolic mitral annular tissue velocity (e') was preserved as 11.7 cm/s, despite inferior vena cava dilation. Respiratory variations in mitral inflow velocities and septal bounces were unremarkable. Cardiac catheterization further showed a 'dip and plateau' pattern with equalization of bilateral ventricular end-diastolic pressure. A preliminary diagnosis of CP was made, and pericardiectomy was performed, increasing the cardiac index from 2.0 to 3.0 L/min/m². Pathological examination revealed marked IgG4-positive plasma cell infiltration and tissue fibrosis. Additionally, the patient's post-operative serum IgG4 level was 679 mg/dL. Given these findings, IgG4-related CP without involvement of other organs was determined as the definitive diagnosis. His clinical status improved without requiring corticosteroid therapy.

Optimal therapy for IgG4-related CP remains elusive due to its rarity. Potential therapeutic options include pericardiectomy, pericardiotomy, and corticosteroid therapy. Further examination through the accumulation of similar cases is crucial to establish definitive treatment approaches for this condition.