Cemento-ossifying fibroma (COF) is a rare benign neoplasm that usually arises from the mandible and maxilla. They most often arise from the tooth bearing areas of these bones.
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In the 2005 WHO histological classification of odontogenic fibromas this tumour is referred as "ossifying fibroma" but in this article the term cemento-ossifying tumour is used to differentiate from peripherally occurring ossifying fibromas.
Other synonyms of cemento-ossifying fibroma besides ossifying fibroma include 7:
- cementifying fibroma
- juvenile (active/aggressive) ossifying fibroma
- discussed separately because of differences in distribution/epidemiology 5
There is confusion in the literature about the nomenclature to use when describing these lesions. Moreover, confusion exists regarding its relationship to other similar entities with various definitions and debate as to whether it is of odontogenic or nonodontogenic osseous origin 1-6, although the 2005 WHO classification currently lists it as a "bone-related tumour" 7.
Cemento-ossifying fibromas are most frequently diagnosed during the third and fourth decades with a distinct female predilection (F:M = 2-5:1) 1,3,6. Occasionally, they are identified in children, in which case they are a more aggressive variant and are known as juvenile aggressive cemento-ossifying fibromas (discussed separately) 3,5.
Clinical presentation is with a solid mass, arising usually from the mandible (62-89%) 3 or maxilla. Most frequently they arise from the premolar region of the mandible (77%) 3. Teeth are often displaced by the growing mass. Other locations within the head and neck have been described 1.
These tumours are composed of fibrous tissue, calcified tissue resembling bone and/or cementum 1,3. The bone-like component is predominant reminiscent of woven bone and is found in more 'mature' lesions 1. In some instances, this entity has been divided into cementifying fibroma and ossifying fibroma depending on the relative amounts of the tumour's constituent tissues. However, in most cases both features are present, warranting the generic term cemento-ossifying fibromas 1.
They are thought to arise from the periodontal ligament, accounting for the usual vicinity to teeth 3.
Plain radiograph and CT
Cemento-ossifying fibromas are usually well circumscribed masses which expand the underlying bone. They are usually small, but can become large. This is particularly the case when they arise from the maxilla or paranasal sinuses because there is more room to expand 1-3. They are initially lucent on x-ray with soft tissue attenuation on CT. As they mature, they gradually develop increasing amounts of calcification/ossification as they mature. They usually expand the bone without cortical breach 3.
Following administration of contrast, the soft tissue component usually enhances on CT 1.
Although masses are composed of a mixture of calcified and non-calcified soft-tissue, as the later is predominantly fibrous, the whole mass is largely of low intensity on MRI 1.
- intermediate to low signal
- focal regions of higher signal may represent fatty marrow in ossified components
- T2: low signal
- T1 C+ (Gd): soft-tissue component may demonstrate some enhancement
Treatment and prognosis
Surgical excision is the treatment of choice and it usually requires bone grafting or reconstructive surgery 1,3. Recurrence following complete excision is generally considered to be uncommon 1,6. However, in some series, it has been reported to be as high as 28% 3.
- 1. Jung SL, Choi KH, Park YH et-al. Cemento-ossifying fibroma presenting as a mass of the parapharyngeal and masticator space. AJNR Am J Neuroradiol. 1999;20 (9): 1744-6. AJNR Am J Neuroradiol (full text) [pubmed citation]
- 2. Yonetsu K, Nakamura T. CT of calcifying jaw bone diseases. AJR Am J Roentgenol. 2001;177 (4): 937-43. AJR Am J Roentgenol (full text) [pubmed citation]
- 3. Kuta AJ, Worley CM, Kaugars GE. Central cementoossifying fibroma of the maxillary sinus: a review of six cases. AJNR Am J Neuroradiol. 16 (6): 1282-6. AJNR Am J Neuroradiol (abstract) [pubmed citation]
- 4. Stergiou GC, Zwahlen RA, Grätz KW. [Multiple cemento-ossifying fibromas of the jaw: a very rare diagnosis] Schweiz Monatsschr Zahnmed. 2007;117 (3): 236-44. [pubmed citation]
- 5. Chang HJ, Donahue JE, Sciandra KT et-al. Best cases from the AFIP: juvenile ossifying fibroma of the calvaria. Radiographics. 29 (4): 1195-9. doi:10.1148/rg.294085240 [pubmed citation]
- 6. Sarwar HG, Jindal MK, Ahmad SS. Cemento-ossifying fibroma--a rare case. J Indian Soc Pedod Prev Dent. 2008;26 (3): 128-31. doi:10.4103/0970-4388.43195 [pubmed citation]