Abstract
Immunoglobulin (Ig) G4-related disease is a recently recognized systemic fibroinflammatory condition characterized by a lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells with elevated circulating levels of IgG4. The disease can either be localized to one or two organs, or present as diffuse multi-organ disease. Furthermore, lesions in different organs can present simultaneously or metachronously. In the pulmonary manefestations, lesions associated with IgG4-related disease have been described in the lung parenchyma, airways and pleura, as well as the mediastinum. We report a case of IgG4-related disease presenting as massive pleural effusion and thrombophlebitis.