Ossifying Fibroma of the Orbital Roof

Abstract

THE TERM is applied to a localized fibro-osseous dysplasia encountered the bones of the face and skull which presents clinically and radiographically as a monostotic expansile lesion. 1,2 When it occurs at the base of the skull, especially the orbital roof, an ossifying fibroma appears as a round or oval radiolucency surrounded by a shell of bone. According to Taveras and Wood, 3 a meningioma that arises in relation to air sinuses of the skull, particularly the sphenoid sinus, often produces a characteristic pattern which has been called 'blistering.' This was first noted by Dyke 4 who referred to it as hypertrophy of the bone forming the posterior ethmoid cells so that these project into the intracranial cavity. Thus, a blistering meningioma may resemble an ossifying fibroma of the orbital roof or sphenoid 5 to some extent radiographically. Histologically, there is also partial similarity. 6