43. A case of eosinophilic angiocentric fibrosis with IGG4-positive plasma cells

Case report Eosinophilic angiocentric fibrosis is a rare fibrotic lesion of the sinonasal and upper respiratory tract. We present a case of eosinophilic angiocentric fibrosis of the maxillary and sphenoid sinuses with infiltration by IgG4-positive plasma cells, raising the possibility of a relationship with IgG4-related sclerosing disease. A 34-year-old female with an unremarkable past medical history presented with a long history of left sided facial pain and congestion unresponsive to corticosteroid therapy. Serum IgG and serum IgG4 levels were not performed. Preoperative CT scans revealed a mass in the left maxillary and sphenoid sinuses. Biopsy of the mass showed fragments of dense fibrous tissue with a prominent concentric arrangement around blood vessels. There was a mild to moderate inflammatory infiltrate including lymphocytes, plasma cells and variable numbers of eosinophils. Isolated blood vessels showed vasculitis with leukocytoclasis. There was no evidence of granulomas, fungi or amyloid. The histological features were consistent with eosinophilic angiocentric fibrosis. Immunohistochemical stain for IgG4 showed the presence of numerous IgG4-positive plasma cells, raising the possibility of a link with IgG4-related sclerosing disease. IgG4-related sclerosing disease is a chronic inflammatory condition in which numerous IgG4 positive plasma cells are seen on immunohistochemical staining and is associated with elevation of serum IgG and IgG4 levels. Since it was first described in the pancreas (autoimmune pancreatitis) in 2001, IgG4-related sclerosing disease has been reported at many sites. As yet, it has not been reported in the sinonasal tract.