Published online Sep 26, 2025. doi: 10.12998/wjcc.v13.i27.108261
Revised: May 26, 2025
Accepted: June 27, 2025
Published online: September 26, 2025
Processing time: 115 Days and 18.3 Hours
Immunoglobulin G4-related disease (IgG4-RD) is a persistent and progressive autoimmune condition marked by inflammation and fibrotic changes in the affected tissues. Cases of IgG4-RD causing pulmonary lesions are relatively rare, and some may be misdiagnosed as pulmonary tuberculosis.
In this report, we present an uncommon instance of IgG4-related lung disease, which was diagnosed through lung tissue biopsy conducted via puncture. A 67-year-old male was hospitalized with a two-month history of cough and sputum production. Chest computed tomography (CT) revealed infiltrative pulmonary tuberculosis in both upper lungs. However, the initial diagnosis was unclear, and the patient received HZRE quadruple therapy for tuberculosis at a local hospital. After 45 days of anti-tuberculosis treatment, the patient's cough and sputum worsened, and he began coughing up blood, prompting transfer to our hospital. Serum tests revealed elevated IgG4 levels. A biopsy of a right lung showed localized fibrous and extensive plasma cell infiltration, with 30-40 IgG4-positive cells per high-power field, and an IgG4/IgG ratio of 40%. These findings led to a diagnosis of IgG4-related lung disease. Following treatment with prednisone and mycophenolate mofetil, follow-up lung CT scans showed significant lesion improvement.
The chest CT findings of IgG4-RD are diverse and nonspecific, often leading to misdiagnosis as pulmonary tuberculosis, especially in primary care settings with limited diagnostic resources. We confirmed the diagnosis of IgG4-related lung disease through histological examination.
Core Tip: Immunoglobulin G4-related disease is a fibrotic inflammatory disease that affects almost all organs and primarily occurs in middle-aged to elderly male patients. It can occur in the mediastinum, airways, lungs, and pleura and is most commonly associated with manifestations outside the chest, which are usually nonspecific. The prognostic characteristics have not yet been determined. Diagnosis relies on a thorough assessment of clinical, biological, and histological findings, as there are no specific biomarkers. Differential diagnoses must always be considered, especially when the disease affects a single organ, is incidentally found on imaging studies, or is unexpectedly diagnosed on pathological specimens.