Eosinophilic Angiocentric Fibrosis: A Review and Update of Its Association With Immunoglobulin G4-Related Disease.

Eosinophilic angiocentric fibrosis is a rare indolent lesion of the head and neck region that has characteristic histologic findings of onionskin fibrosis and prominent eosinophils. Its pathogenesis has been poorly understood and has been most commonly attributed to hypersensitivity or previous trauma. Recently, the lesion has been included in the spectrum of immunoglobulin G4 (IgG4)-related disease. However, few of the existing cases of eosinophilic angiocentric fibrosis have been evaluated for IgG4+ and IgG+ plasma cells. Therefore, we provide an update on the clinical and histologic features of eosinophilic angiocentric fibrosis to increase awareness of the entity and encourage its further characterization as an IgG4-related disease.