diagnosed with IgG4-RD affecting the lungs and pleura; This is a literature report.  The patient is a 71-year-old male with hypertension, coronary artery disease, prostate cancer and chronic obstructive pulmonary disease with a 50-pack year smoking history. The patient started being followed in the pulmonology department after a screening chest CT revealed left hilar fullness and peri-fissural nodules, the largest of which measured 0.4 cm. Repeat CT 2 years later showed unchanged nodules, with two new nodules measuring 0.4 cm. At this point, he elected not to continue surveillance. Two years later, he received a first dose of the Pfizer COVID-19 vaccine and visited urgent care after a week with wheezing and dyspnea which improved with albuterol. However, he returned to clinic with dyspnea 2 weeks after receiving the second dose of the vaccine. He underwent pulmonary function testing which revealed a mixed obstructive and restrictive pattern with reduced DLCO. Six-minute walk test revealed hypoxia requiring 3 L oxygen. Chest CT revealed new left pleural effusion with atelectasis. 1.4 L straw-coloured exudative fluid was removed by thoracentesis which was negative for malignant cells. His symptoms initially improved but worsened again. Repeat CT scan 10 days later revealed large left pleural effusion. He was referred to thoracic surgery and underwent left thoracoscopy with drainage of 2.5 L of pleural fluid followed by pleural biopsy and chemical pleurodesis with insertion of an indwelling tunnelled pleural catheter. Pleural biopsy revealed chronic organizing pleuritis with lymphoid hyperplasia and reactive mesothelial hyperplasia. The pleural catheter continued to drain for 3 months. Eventually, it stopped draining but oxygen requirement increased to 5 L. Repeat CT scan revealed loculated pleural effusions. Thoracentesis was attempted but only 40 ml bloody fluid was drained. Thoracoscopy revealed multiloculated pleural effusions with significant visceral pleural thickening and the patient underwent partial decortication. Pathology report revealed pleural thickening and fibrosis with surrounding pulmonary parenchyma revealing diffuse alveolar damage, lymphoplasmacytic infiltrates, and increased IgG4-positive plasma cells with fibrinous adhesions. At this time, blood IgG4 level was 268 mg/dl. Autoimmune, malignant and genetic conditions with similar presentation were excluded. The patient was diagnosed with IgG4-RD affecting the lungs and pleura, non-pulmonary involvement was not found. He was referred to the pulmonology clinic for further management but he was lost to follow-up. The patient underwent the following laboratory tests and procedures: Alanine aminotransferase: 12 IU/l; Aspartate aminotransferase: 31 IU/l; Biopsy pleura: revealed chronic organizing pleuritis, notes: revealed chronic organizing pleuritis with lymphoid hyperplasia and reactive mesothelial hyperplasia; Blood albumin: 2.3 g/dl; 1.7 g/dl, notes: Pleural fluid; Blood bilirubin: 0.5 mg/dl; Blood cholesterol: 37 mg/dl; Blood creatinine: 0.9 mg/dl; Blood glucose: 83 mg/dl; Blood immunoglobulin G: 268 mg/dl; Blood lactate dehydrogenase: 190 IU/l; 168 IU/l, notes: Pleural fluid; Blood triglycerides: 16 mmol/L; Colour vision tests: Yellow and Hazy; Computerised tomogram thorax: revealed left hilar fullness, notes: revealed left hilar fullness and peri-fissural nodules, the largest of which measured 0.4 cm; showed unchanged, notes: nodules, with two new nodules measuring 0.4 cm; revealed large left pleural effusion, notes: Repeat CT. 10 days later; revealed loculated pleural effusions, notes: Repeat CT; new left pleural effusion, notes: with atelectasis; Eosinophil count: 1 %; FEV1/FVC ratio: 65; Forced expiratory flow: 47.4 %; Forced expiratory volume: 68.9 %; Forced vital capacity: 80.9 %; DLCO/Alveolar volume: 50.4 %; Investigation: non-pulmonary involvement was not found, notes: diagnosed with IgG4-RD affecting the lungs and pleura, non-pulmonary involvement was not found; negative; 36.45; 4 %; Lung diffusion test: 40.4 %; Lung diffusion test: Reduced; Lymphocyte count: 90 %; Mediastinoscopy: multiloculated pleural, notes: effusions with significant visceral pleural thickening and he patient underwent partial decortication; Monocyte count: 5 %; Pathology test: revealed pleural thickening and fibrosis, notes: revealed pleural thickening and fibrosis with surrounding pulmonary parenchyma revealing diffuse alveolar damage, lymphoplasmacytic infiltrates, and increased IgG4-positive plasma cells with fibrinous adhesions; Peak expiratory flow rate: 64.7 %; Protein total: 7.1 g/dl; 5.8 g/dl, notes: Pleural fluid; Pulmonary function test: revealed a mixed obstructive, notes: and restrictive pattern with reduced DLCO; Residual urine volume: 74.1; Total lung capacity: 77.7; Walking distance test: revealed hypoxia; White blood cell count: 3507 ml.; Sender's Comments: Based on available information, a possible contributory role of BNT162B2 vaccine cannot be excluded for the reported event of Immunoglobulin G4 related disease. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-PV202200078678 Same article/patient/drug/event; different dose;