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.