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

Abstract

Diagnostic work-up of IgG4-related disease (IgG4-RD) pleural involvement is a complex task, as there is a broad spectrum of differential diagnoses to consider. We report the case of a patient presenting with relapsing pleural effusion, discussing the main challenges for achievement of a definite diagnosis. A 63-year-old man was admitted for pleural effusion prevalent on the ride side, initially labeled as idiopathic non-specific pleuritis, based on tissue evaluation after a medical thoracoscopy. He was started on steroids with initial improvement, but a later CT scan showed a relapse of pleural effusion associated with diffuse pleural thickening; a subsequent surgical pleural biopsy revealed features suggestive for IgG4-RD, with a marked increase of IgG4 positive plasma cells. High IgG4 serum levels were also found. The present case underlines the importance of increasing awareness of this potential condition among physicians in order to properly guide the diagnostic work-up, as it is likely that IgG4-RD accounts for a proportion of patients with pleural effusions, labeled as idiopathic. In particular, in patients with unexplained pleural effusion, IgG4-RD should be included among differential diagnoses when lymphoplasmacytic infiltration is observed, and a multidisciplinary interaction between clinicians and pathologists appears crucial for an accurate diagnosis and an appropriate management.

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

“…IgG4-related pleural thoracoscopic findings varied from normal 17,19,26 to abnormal, which were expressed as numerous small, white, and dense granular lesions and reddish, hyperemia, and blister-like nodules. 9,10,15,21,22,27 This case showed a reddish, thickened pleura, which differs from the findings of most previous reports. Accumulation of pleural findings may provide new information for the diagnosis of IgG4-RD.…”

“…The risk of postoperative chylothorax should be carefully considered, assuming disruption to the lymphatic pathway. IgG4‐related pleural thoracoscopic findings varied from normal 17,19,26 to abnormal, which were expressed as numerous small, white, and dense granular lesions and reddish, hyperemia, and blister‐like nodules 9,10,15,21,22,27 . This case showed a reddish, thickened pleura, which differs from the findings of most previous reports.…”

IgG4-related diseases involving pleura: a case report and literature review

“…Yang and colleagues also reported that serum IgG4 level was associated with the number of affected organs ( 40 ). However, it is important to be aware that elevated serum IgG4 levels can also be present in a range of other conditions, including healthy individuals, malignant neoplasms, infectious diseases, and other inflammatory conditions ( 8 ). Therefore, relying solely on serum IgG4 levels is insufficient for diagnosing or ruling out IgG4-RD.…”

“…Therefore, relying solely on serum IgG4 levels is insufficient for diagnosing or ruling out IgG4-RD. IgG4 antibodies may serve as markers for immune-mediated processes as part of more complex inflammatory diseases ( 8 ).…”

Pleural effusion due to nonmalignant gastrointestinal disease

“…In this disease, the PF is an exudate with a predominance of lymphocytes, plasma cells and high concentrations of IgG4. Pleural biopsy shows a fibrosing pleurisy with lymphoplasmacytic inflammation and IgG4-positive plasma cells [104].…”