Cemento-ossifying fibroma.

Cemento-ossifying fibromas (COFs) are benign lesions affecting the jaws and other craniofacial bones. They commonly affect adult females between the third and fourth decade of life, predominantly occurring in the premolar/molar region of the mandible. Most of the lesions typically show slow and often expansile growth, centrally within the jaw and characteristically behave in a benign form, but occasionally they may present as an aggressive gigantiform lesion. Radiographically, they appear as well-defined unilocular or multilocular intraosseous masses. The lesion is invariably encapsulated and of mixed radiolucent densities. The tumor may grow quite extensively; thus, the term "aggressive" is sometimes applied. Surgical resection is the treatment of choice.

 The cemento-ossifying fibroma is hard and fibrous, most frequently seen in the jaw or mouth, sometimes in connection with a fracture or another type of injury.


The histology was that of a benign fibro-osseous proliferation composed of bony spicules and espherules admixed with a fibrous stroma. The most distinctive component was the presence of mineralized or calcified "psammomatoid" bodies or ossicles. The ossicles were small with a oval shape without associated osteoblastic rimming. The fibrous stroma was characterized by a spindle cells proliferation that shows a storiform pattern. The lining by a no-keratinized stratified squamous epitelium with overlying ulceration and the superficial parts of the lesion consisted of granulation tissue.The lesion was quite hypocellular with no citologycal atipia and absent of mitotic activity.The histology was consistent with cemento-ossifying fibroma of the oral cavity.
Fibro-osseous lesions of the jaws continue to present problems in diagnosis and classification to clinicians and pathologists, despite the advances in our understanding of this entitie (2,4). The basis on bening fibro-osseus lesions were established by Wladrom and Giasanti in 1973. They made three main categories: fibrous dysplasia, reactive lesions (periapial cemento-osseus dysplasia, focal cemento-osseus dysplasia and florid cemento-osseus dysplasia) and fibro-osseus neoplasms.

Histologicallly it is described as a fibroblastic connective tissue estroma with great cellular variability. The calcified structures consist on rounded or lobulated basophilic masses (cementum-like), trabecuale of osteoid or bone or combination of the two,wich is the most frecuent presentation. In our case, the histology showed bone calcified structures. It is unknown if the cementum-like calcifications are real alveolar cementum because similar calcifications can be found in other fribro-osseus lesions of the skull, placed far from the jaws

There is a type of COF called juvenile active, that is seen in children and young people ranged between 5 and 15 years old. It involves mainly upper maxilla, having a rapid evolution and a tendency to erose surrounding bone. Histology consists on celulo-vascular stroma with varying degrees of giant cells and poor collagen production. Treatment consists on enucleation and curettage. This type of COF has a higher recurrence rate because of its poorer demarcation, and its higher rate of bone infiltration