Pulmonary and Orbital Bifocal IgG4 Disease: Case Report and Literature Review

Introduction: IgG4 disease is an orphan, fibro-inflammatory autoimmune disease of recent discovery whose thoracic involvement is rarer. We report a case of Pulmonary and orbital bifocal IgG4 disease with a review of the literature. Observation: This is a 71-year-old patient with a history of hypertension, dyslipidemia, smoking cessation at 15 PA, with progressive dyspnoea, weight loss of 4 kg with PS = 0 for 2 months. The thoracic CT scan revealed 3 pseudotumoral lung lesions of the LIG, LID and LM. The histology of the two CT-guided lung biopsies and the LIG wedge had objectified inflammatory lesions without signs of malignancy. The evolution was marked by the occurrence of a right orbital edema. The cerebral scanner found a voluminous right orbital inflammatory pseudotumor. Biopsy with histology found fibroinflammatory lesions with lymphoplasmacytic infiltrates and positive immunolabeling with anti-IgG4 antibodies. The PET scanner had objectified pulmonary and pleural parenchymal consolidations and moderately hypermetabolic mediastinal ADP with max SUV between 3 and 6. The patient was put on corticosteroid therapy with a favorable outcome. Conclusion: IgG4 disease is rare and difficult to diagnose despite well-defined and consensual diagnostic criteria and classification. The discovery of new biomarkers facilitates the diagnosis and monitoring of patients. Well-codified corticosteroid therapy is effective but possibility of recurrence. The current challenge remains the lack of data on the follow-up of these patients to assess the risk of neoplasia (lymphoma).