Common Characteristics of Sinonasal Inflammation Associated with IgG4-Related Disease and Other Chronic Inflammatory Diseases: A Retrospective Observational Study

Abstract

Plain Language SummaryImmunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by elevated serum IgG4 levels and tissue IgG4-positive cells. A part of IgG4-RD patients has sinonasal lesions. Because other inflammatory diseases also have features common to IgG4-RD, accurate knowledge of IgG4-RD is required. However, very little is known about IgG4-related rhinosinusitis. This study retrospectively analyzed clinicopathological features of IgG4-related rhinosinusitis and compared IgG4-related rhinosinusitis with other inflammatory diseases. Seven patients with sinonasal lesions and high serum IgG4 levels were retrospectively reviewed. Six of 7 patients were diagnosed with IgG4-RD, while one was diagnosed with granulomatosis with polyangiitis (GPA). In the 6 patients with IgG4-RD, intranasal findings showed nasal polyps in 3 patients (50%) and computed tomography showed ethmoid sinus involvement in 5 patients (83%), which shared common features with eosinophilic sinusitis (ECRS). However, no patients showed histopathological eosinophil infiltration. Although the patient with GPA revealed tissue infiltration of IgG4-positive cells in the nasal biopsy, the patient also had saddle nose and positivity of myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA), which indicated GPA. We diagnosed the patient with GPA, which is a known mimicker of IgG4-RD. In this study, the patients with IgG4-related rhinosinusitis had clinical and pathological characteristics similar to those of ECRS and GPA. IgG4-related rhinosinusitis should be diagnosed based on not only tissue infiltration of IgG4-positive cells but also systemic findings including nasal findings and serum ANCA levels. IgG4-RD should be ruled out in patients with eosinophilia without histopathological eosinophil infiltration.