allergic fungal sinusitis presenting as a paranasal sinus tumor

we present a case of allergic fungal sinusitis (afb) in a 20-year old man with few months' history of bilateral nasal obstruction and discharge with unilateral proptosis that underwent maxillary antrostomy due to the mass in paranasal sinuses. histological examination of tissue showed branching fungal hyphae interspersed with allergic mucin without fungal invasion to soft tissue. the patient received local steroid for 4 months and had no problem during follow up. fungal culture was performed and bipolaris fungus grew. although most dematiaceous fungal infections occur in immunocompetent patients, the incorrect diagnosis and insufficient treatment may be life threatening.