An unusual case of purulent constrictive pericarditis with Hyper-IgG4-related histological findings on biopsy

Abstract Constrictive pericarditis results from chronic inflammation with scarring and loss of the elasticity of the pericardial sac. It is a chronic disease, even though it can result of acute or subacute pericarditis. Etiology varies widely depending on the population studied, viral infections and tuberculosis are the main causes in developing countries, albeit other causes are frequent such as connective tissue disorders, post-cardiac surgery, post-radiation, malignancy, and trauma. Patients usually present with symptoms related to fluid overload and diminished cardiac output. Transthoracic echocardiography is essential as a diagnostic tool. We report a case of a man with a constrictive pericarditis diagnosis. We had a high clinical suspicion of tuberculosis, nevertheless, a non-typhoidal Salmonella group D was evidenced from the pericardial fluid. Histopathology was consistent with Hyper-IgG4-related pericarditis with fibrosis, inflammatory infiltrate of plasma cells, and immunohistochemistry positive for IgG4 cells. Pericardial manifestations of IgG4-RD have not been included in the 2019 IgG4-RD entry classification criteria, endorsed by the EULAR/ACR, however, few cases with isolate pericardial involvement have been reported in the literature.