Sinonasal eosinophilic angiocentric fibrosis: a report of four cases and review of literature.

Eosinophilic angiocentric fibrosis (EAF) is a rare, benign condition of unknown etiology involving the sinonasal tract and the upper respiratory airways, and rarely, larynx, and orbit. We report four cases of EAF identified, in three women and one man, aged 31, 57, 27, and 51 years, respectively. The patients complained of sinonasal obstructive symptoms of long duration, nasal masses, epiphora, and/or proptosis. Histologically, all cases demonstrated a dense fibrotic stroma with a perivascular "onion-skin" whorling pattern, and a dense inflammatory infiltrate consisting of lymphocytes, plasma cells, eosinophils, and some neutrophils. In addition, one patient demonstrated modest acute neutrophilic inflammation with focal endothelial proliferation. No patient exhibited clinical or histological evidence of Wegener's granulomatosis, granuloma faciale, Kimura's disease, and malignant lymphomas. Surgical excision was performed in all cases, and to date, medical therapy has been of limited help. The clinical and histopathological features and differential diagnoses of this underreported EAF condition are discussed.