P187

I. Arunsurata (Dr), S. Disayabutr*a (Dr), J. Tscheikunaa (Dr)

a Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, THAILAND

* supparearg@gmail.com

Background: The exudative pleural effusions have various causes with up to 20% remaining undiagnosed despite a diagnostic workup. The IgG-4-related disease is a rare fibroinflammatory disorder that can affect various organs and can be difficult to diagnose. We reported a case of IgG4-related pleuritis without other systemic manifestations.

Case report: A 50-year-old man with a history of giant cell tumor of the left distal femur 10 years ago with no evidence of distant metastasis. In 2018, he presented with asymptomatic right pleural effusion. The pleural fluid was turbid straw color with lymphocytic predominance. Pleural LDH was 2,594 U/L, protein 9.5 g/dL, glucose <4 mg/dL, cholesterol 144 mg/dL, and triglyceride 18 mg/dL. The microbiological studies were all negative. Pleuroscopy revealed diffuse pleural thickening with yellowish plaques. The histopathology showed xanthogranulomatous pleuritis and pleural fibrosis. Computed tomography (CT) of the chest was performed later which showed consolidation and round atelectasis of the right lower lobe with loculated right pleural effusion. Transbronchial lung biopsy were done with non-diagnostic results. There was no specific treatment and the cause of pleuritis cannot be identified. The patient had no respiratory symptoms with stable minimal right pleural effusion during a 2-year follow-up. Two years later, he developed a new left pleural effusion without systemic symptoms. CT chest revealed no change of loculated right pleural effusion and round atelectasis of the right lower lobe. The profile of the left pleural fluid and pleuroscopic findings were similar to the previous examination on the right side. The histopathological results showed dense infiltration by plasma cells with eosinophils and multifocal fibrotic changes. The immunostaining was compatible with IgG-4-related disease.

Conclusion: The exudative pleural effusion with lymphocytic predominance with high levels of LDH and protein and low glucose without other explainable cause, the IgG-4-related disease should be considered as a differential diagnosis.

Disclosure of funding source(s): none