A Case of Immunoglobulin G4-Related Sclerosing Disease of the Paranasal Sinus Mimicking Nasal Malignancy

ABSTRACT

Immunoglobulin G4 (IgG4)-related sclerosing disease (RSD) is a chronic inflammatory disorder characterized by elevated serum IgG4 levels as well as an abundant infiltration of IgG4-positive plasmacytes. Involvement of the paranasal sinus is very rare, so it is difficult to make an accurate diagnosis. Hence, various differential diagnoses, which typically include elevated serum IgG4 levels and the infiltration of IgG4-postive cells into tissues, need to be excluded, especially for malignant diseases and mimicking disorders. Systemic corticosteroids are generally effective at inducing IgG4-RSD remission. Recently, a 43-year-old woman presented with a mass originating from the ethmoid sinus, suggesting malignancy. The patient underwent biopsy of the lesion. The pathologic specimen revealed the magnitude of IgG4-positive plasma cell infiltration, which was consistent with IgG4-RSD. In addition, serum IgG4 levels were markedly increased. After glucocorticoid treatment, the serum IgG4 levels decreased and the symptoms improved. We present a rare case of IgG4-RSD with isolated involvement of the paranasal sinuses.