[Two cases of IgG4-related disease with pleural effusion].

We describe 2 cases of IgG4-related disease with pleural effusion in elderly men. Both patients had elevated serum IgG4 levels, and the characteristics of their pleural effusion were similar. Patient 1 had pericardial effusion and retroperitoneal fibrosis, and a biopsy specimen from the pericardium showed infiltration of abundant IgG4-positive plasma cells with fibrosis. Because his pleurisy, pericarditis and retroperitoneal fibrosis responded...