The cemento-ossifying fibroma is classified as an osteogenic neoplasm of the jaws. It commonly presents as a progressively growing lesion that can attain an enormous size with resultant deformity if left untreated. A case of a large cemento-ossifying fibroma involving the left mandible is described in a 15 year old male patient. The clinical, radiographic and histological features as well as surgical findings are presented. The treatment of choice of this lesion is also emphasized. Two years after surgery, there was no evidence of recurrence and the transosseous wire used to immobilize the fracture was found to be completely buried in the jaw bone.
Despite the fact that cemento-ossifying fibromas of the maxilla may be quite large and locally aggressive, en-bloc excision is achieved by gentle blunt dissection, with the whole tumour mass peeled out from the adjacent structures. Until recently different fibro-osseous tumours that contained cementum were classified together as "cementomas". In 1992 The World Health Organization adopted a new classification that included these fibromas as benign osseous tumours. While such tumours of the mandible are common, those of the maxilla are rare. They are growth products of periodontal membrane remnant. The triggering mechanism in the formation of cementum outside the periodontal membrane remains unclear. We present a 35-year-old woman who had a giant expanding lobular mass in the right maxilla of 5 years duration. She had visual disturbances and nasal obstruction, and was treated successfully by surgical en-bloc resection of the tumour through an infraorbital transverse incision. The differential diagnosis included fibrous dysplasia, osteoid osteoma, osteoblastoma, chronic sclerosing osteomyelitis, ameloblastoma, squamous cell carcinoma of the maxillary sinus, calcifying epithelial odontogenic tumour (Pindborg tumour) and calcifying odontogenic cyst (Gorlin cyst). Histopathological examination confirmed a cemento-ossifying fibroma.