CASE REPORT Immunoglobulin G4Related Sclerosing Disease Mimicking Invasive Tumor in the Nasal Cavity

SUMMARY: IgG4RSD affecting the nasal cavity and paranasal sinuses is extremely rare. A 71-year-old man presented with an invasive mass in the nasal cavity and paranasal sinuses that was confirmed by immunostaining to be IgG4RSD. The occurrence of this disease in the nasal cavity and paranasal sinuses can resemble a malignant tumor on diagnostic imaging. ABBREVIATIONS: IgG4 immunoglobulin G4; IgG4RSD immunoglobulin G4related sclerosing disease IgG4RSD involves multiple organs, particularly exocrine or-gans such as the salivary glands, pancreas, and biliary tracts.1 When it affects the head and neck, it commonly involves the salivary, lachrymal, and pituitary glands. There is insufficient radiologic data for IgG4RSD affecting the nasal cavity and paranasal sinuses.1-3Wepresent a case of IgG4RSDmimicking an invasive malignant tumor in the nasal cavity and maxillary sinuses on both sides. Case Report A 71-year-old man who had a brain contusion 25 years earlier com