Journal of Research in Medical Sciences1735-199516220110219A case report of cemento-ossifying fibroma presenting as a mass ofthe ethmoid sinus52075207ENAliHekmatniaMasihSabooriAmirhosseinGhazaviResident of Radiology, Department of Radiology, Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran. amirhosseinghazavi@yahoo.comParvinMahzouniNazilaTayariFarzanehHekmatnia2010032720100801Cemento-ossifying fibroma is a lesion containing both fibrous and osseous components. Such lesions include fibrous dysplasia, ossifying fibroma, cemento-ossifying fibroma and cementifying fibroma. Periodontal membrane is the origin of fibro-osseous lesions other than fibrous dysplasia.Here a clinical case of a young woman referred for evaluation of a mass in the right side of face between eye and nose is presented. The first time she noticed the mass was 2 years ago and was growing larger inwards. She was treated with surgical resection.In this case of a cemento-ossifying fibroma, histological interpretation was critical, and was the basis of correct treatment.KEYWORDS: Fibroma, Ossifying, Ethmoid Sinus, Tomography, X-Ray Computed, Magnetic Resonance Imaging.