Pleural Involvement in IgG4-Related Disease: Case Report and Review of the Literature

Metachronous bilateral immunoglobulin G4-related pleuritis: A case report and literature review

Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized disease, and therefore its clinical features are not yet fully understood. Here, we describe a surgical case of metachronous bilateral IgG4-related pleuritis and postoperative chylothorax. This case could provide key insights into the pathology of IgG4-RD from a surgical perspective. We present a 70-year-old woman who had a right pleural mass. Video-assisted thoracoscopic pleural mass resection was performed, and the patient was diagnosed with right-sided IgG4-related pleuritis. Two years later, she was also diagnosed with left-sided IgG4-related pleuritis. We suspected the presence of IgG4-positive plasma cell infiltration. Additionally, she experienced a complicated postoperative chylothorax on the left side. It is important to consider the altered course of lymphatic vessels when extensively removing the pleura near the right thoracic duct. The occurrence of metachronous bilateral IgG4-associated pleuritis has not been previously reported, making this case particularly significant for understanding the pathology of IgG4-RD from a surgical standpoint.

New biomarkers for the diagnosis of pleural effusion

Background

Persistent undiagnosed effusion is present in approximately 15% of all causes of exudative effusion. Pleural effusion caused by immunoglobulin G4 (IgG4) is a new type of pleural effusion. Tumor markers such as Carcinoembryonic antigen (CEA) may play a role in the diagnosis of malignant pleural effusion. This study aimed to evaluate the use of serum Immunoglobulin G4 and carcinoembryonic antigen in diagnosing pleural effusion.

Methods

This observational descriptive cross-sectional study comprised 89 individuals with exudative pleural effusion who visited the Assiut university hospital's chest department. All patients were examined and asked about their medical history. Also, chest X-ray, MSCT chest, transthoracic ultrasonography, pleural fluid analysis and cytology, serum level of carcinoembryonic antigen, and immunoglobulin G4 were performed. In addition, pleural biopsy, bronchoscopy, and thoracoscopy were performed when required.

Results

In comparison to another diagnosis, the level of serum IgG 4 was observed to be substantially greater in individuals with IgG4-associated effusion (725± 225.45). Patients with malignant mesothelioma (70± 16.24) and metastatic adenocarcinoma (93.52± 19.34) had lower levels of IgG4. In contrast, the serum level of CEA was significantly higher in individuals with malignant mesothelioma (79.50± 29.47) and metastatic adenocarcinoma (68.71± 28.98). Patients with para-pneumonic effusion had a minor serum level of CEA (0.36 ± 0.26). At cutoff point > 152 mg/dl serum IgG-4 had 100% sensitivity and 94% specificity in the diagnosis of IgG4 related pleural effusion with an overall accuracy of 95.3% and area under the curve of 0.97. At the cutoff point > 5 ng/ml serum CEA had 77% sensitivity and 100% specificity in diagnosing malignant pleural effusion with an overall accuracy of 91.1% and area under the curve of 0.88.

Conclusion

Serum IgG4 higher than 152 mg/dl has good diagnostic accuracy in cases of undiagnosed pleural effusion. Carcinoembryonic antigen aids in diagnosing malignant pleural effusion with a cutoff point higher than 5 ng/ml in serum.

Trial registration

ClinicalTrials.gov registration ID NCT03260088