International Journal of Clinical & Medical Images

Ossifying fibroma (OF) is a fibro-osseous lesion with benign nature. It was first described by Menzel in 1872. It is commonly seen in the head and neck areas. It has an aggressive and destructive nature [1]. This CTscan shows a hyperdense mass in left ethmoidal sinus in 11 years old boy. Transnasal endoscopic resection was performed and histopathological examination confirmed the diagnosis of OF. The present case and also his CTscan are notable because involvement of the ethmoid sinus is rare in this condition with only 48 cases reported in the literature until June 2011.