Immunoglobulin G4-related thoracic disease: clinical and radiological findings of an eastern mediterranean cohort

Background and Aim: Thoracic involvement of Immunoglobulin G4-related disease (IgG4-RD) is relatively rare and can be easily overlooked due to its asymptomatic nature. This study aimed to determine the frequency and patterns of thoracic involvement of patients with IgG4-RD. Materials and Methods: 90 patients (male/female: 47/43, mean age: 57.7±15.5 years) with IgG4-RD were reviewed retrospectively. All computed tomography (CT) scans were re-evaluated by two thoracic radiologists and IgG4-related thoracic disease was assessed on four compartments: Mediastinum, pulmonary parenchyma, airways, and pleura. IgG4-related thoracic disease was categorized as: definite, highly probable, probable and possible. Results: 64 patients had undergone at least one thorax CT examination and 18 (28%) were recorded to have IgG4-related thoracic disease. The rate of IgG4-related thoracic disease increased by 20% and reached a ratio of 48.4% (n=31) after re-evaluating registry data dedicatedly for thoracic findings. Mediastinum was the most frequently involved compartment in 16 (51.6%) patients. Other organ involvements were more prevalent and IgG4 levels were higher in patients with thoracic involvement. Eosinophils were significantly elevated in patients with thoracic involvement (p=0.023). Conclusion: IgG4-related thoracic disease is heterogeneous and likely underestimated. Mediastinum is the most frequently involved compartment. IgG4-related thoracic disease should be evaluated at initial diagnosis. Elevated serum IgG4 levels and eosinophils, increased number of organ involvements can be indicators for thoracic involvement.