Thoracoscopic Findings in IgG4-related Pleuritis

A 46-year-old Japanese man was admitted to our hospital with a 1-year history of dyspnea and persistent right-dominant bilateral pleural effusions. Chest and abdominal computed tomography (CT) revealed no notable findings apart from the bilateral pleural effusions. 2-deoxy-2-[(18)F]-fluoro-D-glucose (FDG) positron emission tomography-CT showed no accumulation of FDG in the thorax and abdomen. Thoracoscopy revealed numerous small (approximately 2-3 mm in size), blister-like nodules on the left parietal pleura extending from the lower third of the chest wall to the diaphragm. A pathological examination revealed lymphocyte and plasma cell infiltrates with increasing numbers of IgG4-positive plasma cells in the fibrotic pleura, indicating IgG4-related pleuritis.