Right ethmoid eosinophilic angiocentric fibrosis with orbital extension.

INTRODUCTION: Eosinophilic angiocentric fibrosis (EAF) is a slowly progressive, benign disease involving the mucosa of the upper airways or, more rarely, the orbit. It belongs to the spectrum of IgG4-related disease. CASE REPORT: The authors report the case of a 61-year-old man who presented with orbital involvement (visual loss, pain, proptosis, and eyelid oedema), headache and nasal obstruction. Imaging revealed a right ethmoido-orbital mass infiltrating the periorbital fat and enveloping the optic nerve. Histological examination concluded on a diagnosis of EAF in the presence of perivascular infiltration by inflammatory cells, predominantly eosinophils, and zones of "onion skin" fibrosis. Immunohistochemistry attributed these lesions to IgG4-related disease. Initial treatment with corticosteroids followed by dapsone failed to control the disease and resulted in severe steroid dependence. Surgical ethmoidectomy with resection of the lamina papyracea was performed to allow displacement of the eyeball into the nasal cavity in the event of another episode. DISCUSSION: The combination of surgery and rituximab achieved lasting pain relief with no recurrence of exophthalmos.