Immunoglobulin G4-related disease mimicking lymphoma: Challenging to diagnose

Abstract Practically, all major organ systems can be impacted by an immune-mediated fibro-inflammatory condition known as immunoglobulin G4-related disease (IgG4-RD). Even though it is not unusual, the level of orbital involvement in IgG4-RD can change depending on where the lymphoplasmacytic infiltrate is located. We address a case of IgG4-RD in this study who presented with large bilateral upper and lower eyelids swelling, mediastinal lymphadenopathy, and elevated serum IgG4. It was necessary to do a histopathology examination to confirm the diagnosis of the IgG4-RD and rule out any possible mimicking hematological conditions. In conclusion, this case report emphasizes the value of clinical symptoms and imaging in reducing the number of potential diagnoses, although biopsy remains a gold standard to confirm the diagnosis of IgG4-RD.