Cemento-Ossifying Fibroma in Maxillofacial Region: A Series of 16 Cases

Abstract

Introduction

Cemento-ossifying fibroma is considered as a benign osseous tumour, closely related to other lesions such as fibrous dysplasia and cementifying periapical dysplasia. These lesions occur in the second to the fourth decade of life. It is a bony tumour of maxilla and mandible of possibly odontogenic origin with aggressive behaviour and high tendency for recurrence. Radiologically, the lesion appearances varied ranging from radiolucent cyst-like appearance to mixed and/or radiopaque areas.

Aims and objectives

The article attempts to highlight the importance of clinical, imaging aspects and histopathology in diagnosis of cemento-ossifying fibroma along with management and long-term follow-up.

Materials and methods

This retrospective study was done on histologically diagnosed 16 fibro-osseous lesions. These patients were treated under general anaesthesia at our institute. The demographic data, radiographic features, and histopathologic findings were analysed and compared. The treatment and follow-up data were also recorded.

Results

Cemento-ossifying fibroma showed higher predilection for female than for male patients and with an equal number of cases reported in maxilla and mandible with no signs of recurrence in long-term follow-up of 15 years.

Conclusion

Complete surgical excision of cemento-ossifying fibroma comes out to be only effective treatment that gave satisfactory results and can be considered as a definitive treatment modality.

Introduction

Cemento-ossifying fibroma (COF) is a rare, benign fibro-osseous lesion of the jaws exhibiting well-circumscribed, unilocular, or multilocular radiolucency mixed with radiopacity based on the type of mineralized tissue it contains. The origin of COF has been associated with the periodontal membrane that has multipotent cells capable of forming cementum, lamellar bone, and fibrous tissue. It can affect both mandible and maxilla, particularly the mandible. This bone tumour consists of highly cellular, fibrous tissue which consists of varying amounts of calcified tissue resembling bone, cementum, or both. Clinically, this tumour manifests as a slow-growing mass that may be asymptomatic and would be seen on a routine orthopantomogram. The recurrence of these benign tumours following surgery is considered rare. However, Eversole and his collaegues in a study on 64 cases of COF reported a recurrence rate of as high as 28% following surgical curettage of these lesions [1]. Radiologically, cemento-ossifying fibroma usually manifests as a well-delimited unilocular lesion containing variable amounts of radiopaque material. The histological representation usually contains cementum, immature bony trabeculae that may also be seen in fibrous dysplasia. A definitive diagnosis is usually established based on the correlation between clinical, radiological, and histological findings.

Clinical Description of 16 Cases

Archival data of cases, histopathologically identified as COF operated in the department of oral and maxillofacial surgery at our institution over a period of 15 years, were analysed. A total of sixteen cases were retrieved with complete relevant clinical, radiographic, and histopathological data. The final diagnosis of cemento-ossifying fibroma was based on histologic appearance.

Age, sex, site of lesion, and presenting features were analysed. The series comprised of 6 male and 10 female patients. The mean age was 26.5 years with a range of 10–48 years. There was equal involvement of both maxilla and mandible (8 lesions each).

The clinical features of all patients are shown in Table 1. The commonest clinical feature was gradually increasing swelling over affected area followed by difficulty in speech and mastication; 6 patients presented with history of painful diffuse swelling which was gradually increasing in size while other 10 cases had no history of pain. Hard and firm texture and immobile nature of the lesion were present in all patients. Radiographic root resorption and mobility of teeth were present at involved sites in 14 cases; the rest 2 cases revealed firm teeth with no evidence of root resorption. One case had a history of discharge from lesion.

Table 1.

Clinical presentation of 16 cases

Case no	Gender	Age (years)	Site	Oral examination
1	M	14	Right posterior maxilla	Painless hard and firm swelling on buccal side extending to palatal region
2	F	18	Right body of mandible	Diffuse swelling with buccolingual expansion extending from right incisor to second mandibular molar
3	M	10	Right posterior mandible	Hard and firm mass with buccal obliteration in the region of right mandibular first premolar to distal of mandibular first molar
4	M	30	Right posterior maxilla and infratemporal region	Hard expansile mass in the right maxillary tuberosity region involving posterior hard palate
5	M	18	Left posterior maxilla	Firm swelling of about 3 × 6 cm size in left buccal vestibule extending from left maxillary canine to distal of second molar
6	F	48	Left posterior mandible	Diffuse swelling with buccolingual expansion and with lingual displacement of teeth
7	M	26	Right zygoma region	Diffuse swelling obliterating the upper vestibule
8	F	42	Anterior maxillary region	Hard and firm swelling in the anterior maxilla with labial vestibule obliteration extending palatally
9	F	27	Maxillary premolar region	Painless hard and firm swelling in the premolar region with palatal displacement of tooth
10	F	25	Left posterior mandible	Hard and firm mass with buccal obliteration in the region of left mandibular canine to distal of second molar
11	M	32	Left posterior mandible	Painless diffuse swelling with buccolingual expansion
12	F	40	Anterior maxillary region	Diffuse, hard, and firm swelling in the anterior maxilla causing mobility in the teeth
13	F	14	Right mandibular body	Hard and firm mass with right buccal vestibule obliteration in the region of mandibular posterior teeth
14	F	40	Maxillary posterior region	Diffuse swelling with palatal extension and mobility of teeth
15	F	30	Right posterior mandible	Hard expansile lesion in the right posterior region of mandible
16	F	11	Lingual side of mandible w.r.t central incisors	Hard swelling in lingual vestibule

On radiographic examination, varied appearances ranging from radiolucent cyst-like appearance to mixed and/or radiopaque areas were seen. Orthopantomograms and computed tomography scans were evaluated to assess the presence or absence of scalloping, lesion definition at periphery, and effect on associated teeth and other anatomical structures. Fourteen cases showed well-defined multilocular lesions out of which seven (43.7%) were radiopaque, five (31.2%) were mixed radiolucent–radiopaque, and two (12.5%) were radiolucent lesions while only two lesions (12.5%) showed unilocular radiolucency. Six out of eight large ossifying fibromas of the mandible showed characteristic downward bowing of the inferior cortex of the mandible. There was buccopalatal/buccolingual cortical plate expansion also seen in fifteen cases. In four out of eight cases of maxilla, swelling was extending palatally. One case was found to had extension in infratemporal region, and one had extension in zygoma region.

Histopathologically, parameters such as type of bone (mature/immature), cellularity, presence of cementum-like material, and nature of stroma were assessed. All the sixteen cases presented immature woven bone, cementum-like material, few foci of osteoid and proliferative cells with variable thickness of the lining epithelium.

The treatment planning was done according to histologic nature, size, and site of the lesion. All the cases of cemento-ossifying fibromas present in mandible were easily shelled out of the bony cavity. In the case of maxilla, dissection of surrounding tissue was done to remove the lesion completely. The treatment given, follow-up period, and outcomes of patients are shown in Table 2. In ten out of sixteen cases, enucleation and curettage of lesion were done. Five cases were treated with local resection of lesion, whereas en bloc resection was done in one case. Recurrence did not occur in any patient of cemento-ossifying fibromas over a follow-up period of about 15 years.

Table 2.

Treatment and outcomes

Case no	Surgical procedure	Follow-up	Outcome
1	Enucleation and curettage	10 years	No recurrence
2	Enucleation and curettage	5 years	No recurrence
3	Enucleation and curettage	7 years	No recurrence
4	Local resection of tumour	6 years	No recurrence
5	Enucleation and curettage	10 years	No recurrence
6	Local resection of tumour	4 years	No recurrence
7	Enucleation and curettage	4 years	No recurrence
8	Local resection of tumour	3 years	No recurrence
9	Enucleation and curettage	5 years	No recurrence
10	Enucleation and curettage	5 years	No recurrence
11	Enucleation and curettage	4 years	No recurrence
12	Local resection of tumour	4 years	No recurrence
13	Local resection of tumour	8 years	No recurrence
14	Enucleation and curettage	8 years	No recurrence
15	Enucleation and curettage	15 years	No recurrence
16	En bloc resection with lingual corticotomy	4 years	No recurrence

Discussion

Fibro-osseous lesions of the jaws have been classified by Waldron and Kramer et al. [2]. These benign fibro-osseous lesions can arise from any part of the facial skeleton and skull with over 70% of cases arising in the head and the neck region. Various classifications were proposed to classify these lesions; Menzel [3] gave the first description of a variant of ossifying fibroma, which was a benign fibro-osseous neoplasm, calling it as a cemento-ossifying fibroma in 1872.

Larger lesions with size over 80 mm in their greatest diameter have been termed as giant ossifying fibroma [4]. In 1992, WHO grouped such lesions under the common denomination of COF on the grounds that they represent histological variants of a same type of lesion [5]. The recent WHO (2005) edition of the classification of odontogenic neoplasms has replaced the term cemento-ossifying fibroma with ossifying fibroma [6]. The origin of cemento-ossifying fibroma is not clearly understood. Most of cases reported in the literature found to have a history of trauma [7]. In our series, only three cases gave a history of traumatic injury. It is considered that these lesions arise either by reactive or by developmental origin, from the periodontal membrane which contains pluripotent cells [8]. These cells under certain pathologic conditions are capable of producing tumours composed of cementum, lamellar bone, or fibrous tissue [9]. A more aggressive form of COF which occurs in younger individuals designated as juvenile cemento-ossifying fibroma [10] was also observed in two of our cases.

An interdisciplinary approach is required to diagnose COF on the basis of clinical, radiographic, and microscopic features [11]. Clinically, COF presents as a slow-growing tumour of the jaw and is commonly seen in young and middle-aged adults. There is a marked predilection for the females [5]. In our case series, also there were 10 female and 6 male patients (5:3). The premolar–molar region of mandible is more commonly involved than maxilla although cases have been reported in the other craniofacial bones. 70% cases involve the mandible, but a significant percentage (22%) has been found in the molar region of the maxilla, ethmoidal, and orbital regions, also exceptionally in petrous bone [5]. In the present study, there was equal involvement of maxilla (50%) and mandible (50%).

The lesions are generally asymptomatic until the growth produces swelling resulting in mild facial asymmetry [5]. In the present study, ten patients reported with asymptomatic swelling, whereas other patients presented with complaint of pain that persisted for a long duration with the range varied from 6 months to 4 years.

Displacement and root resorption of teeth adjacent to the lesion may be an evident clinical feature which was also seen in all of our cases except two cases, suggesting that tumour was in active stage. Most of the lesions present centrally within the jaws show slow and expansile growth and characteristically behave in a benign form. Occasionally, they may present as an aggressive gigantiform lesion [12]. Ossifying fibromas are spherical to egg shaped, expand cortices equally, and are heterogenous because of an inconsistent distribution of their osseous and fibrous components [13]. In our cases, patients presented with these similar features.

The radiographic pattern for cemento-ossifying fibroma has been described by various authors as follows:

1. Waldron and Giansanti [14] had reported that COF showed lytic lesions in 26% of cases, 63% lesions were lytic with radiopaque foci, and 12% lesions showed diffuse and homogenous appearance.

2. Titinchi et al. [15] carried out a retrospective study which revealed almost 49.2% lesions of ossifying fibroma as radiopaque, 34.9% lesions as mixed radiolucent–radiopaque, and only 15.9% lesions as radiolucent. Also, 84.1% lesions were unilocular in panoramic radiographs and only 15.9% cases were multilocular. The multilocular lesions were more prominent in mandibular posterior regions and in patients younger than 20 years. In our case series, the multilocular radiolucency was seen in all cases of mandibular posterior region.

3. Barberi et al. [16] categorized the radiographic pattern as follows: defined lesion without scelerotic rim (40%), defined lesion with sclerotic rim (45%), and lesion with ill-defined border (15%).

Titinchi et al. [15] found almost 93.6% lesions with well-defined margins easily distinguishable from healthy bone. This was similar to our cases in which 15 cases presented with well-defined margins on radiographs.

A study of 43 cases of ossifying fibromas presented by Eversole et al. [17] in 1985 revealed six radiological variations among which 9% of cases showed features of radiolucency with radiopaque dense foci, ground glass opacification along with root divergent or resorption; these features could also been seen in our 14 cases (87.5%). An important diagnostic feature of COF is centrifugal growth pattern rather than a linear one, and therefore, the lesions grow by expansion equally in all directions and present as a round tumour mass. The borders are well defined, and a thin radiolucent line representing a fibrous capsule separates the lesion from the surrounding bone [18]. Large mandibular lesions may cause characteristic thinning and downward “bowing” of inferior border [19]. Both of these features were expressed in six patients of mandibular lesion.

Provisional diagnosis of cemento-ossifying fibroma in our case series was made on the basis of clinical and radiographic features. The differential diagnosis included fibrous dysplasia, cemento-osseous dysplasia, calcifying epithelial odontogenic tumour, calcifying odontogenic cyst, cementoblastoma, florid cemento-osseous dysplasia, Paget’s disease, and odontoma.

An ossifying fibroma is a benign tumour in bone, whereas fibrous dysplasia is a maturation defect of bone and presents as blending margin with the surrounding bone along with linear expansion of cortex which is not seen in OF. Both of the lesions present with distinctly different radiographic and CT scan images [20]. On the other hand, cemento-osseous dysplasias show the presence of wide sclerotic border of the bony cysts and are multifocal, while COF is not.

Radiographically, COF resembles calcifying epithelial odontogenic tumour and calcifying odontogenic cyst, if associated with impacted teeth, making it difficult to distinguish both [21]. Ossifying fibroma may also resemble a cementoblastoma or florid cemento-osseous dysplasia if occurs around tooth roots. These can be distinguished from an ossifying fibroma by their radiographic appearance.

An incisional biopsy and/or an alkaline phosphatase determination is necessary to rule out osteosarcoma or Paget’s disease [13]. Odontoma will show presence of tooth-like structure in the lesion, whereas COF shows radiopaque foci of calcified areas. The diagnosis can be confirmed by other features and histologic appearance [20].

Microscopically, COF reveals many delicate interlacing collagen fibres, seldom arranged in discrete bundles, interspersed with large numbers of active, proliferating fibroblasts, and cementoblasts [22]. Rounded, cementicle-like masses may be present, either alone or together with the trabeculae of woven or lamellar bone [13]. Endo et al. attempted to distinguish COF from ossifying fibroma and fibrous dysplasias using immunohistochemistry by assessing Keratan sulphate and chondroitin-4-sulphate. It was found that COFs showed significant immune reactivity for keratan sulphate, while intense immunostaining for chondroitin-4-sulphate was observed in ossifying fibromas and fibrous dysplasias [23, 24].

The surgical management of COF depends mainly on its clinical and radiological presentation and usually entails one of the following methods, namely enucleation, curettage, and surgical resection of the tumour with or without continuity defect. The smaller lesions can be treated with enucleation and primary closure, whereas moderately large lesions have to be treated aggressively with local excision/curettage of the lesion wherever applicable. Curettage of smaller lesions is performed when there is no cleavage margin, on radiographic examination, for complete enucleation of the lesion. Larger COF requires more radical approach owing to tendency for recurrence after incomplete removal. In these cases, mono-bloc resection should be performed along with bony reconstruction either by iliac crest nonvascularized bone graft or by free fibula flap depending upon size and volume of the defect. Due to radio-resistant character of the lesions and incidence of radiation-induced sarcomas, radiotherapy is absolutely contraindicated for the management of ossifying fibroma [15, 18].

Prognosis of the lesion is known to be fair, and recurrence after removal of the tumour is rarely encountered. However, recurrence of COF is higher in the case of maxillary COF compared to the mandibular ones due to the greater difficulty in their surgical removal and larger size at the time of presentation [18]. Complete surgical removal of the lesion as early as possible has been advised by numerous investigators [15]. Long-term follow-up of these patients is mandatory as recurrences can occur for up to 10 years following treatment. There is no evidence that cemento-ossifying fibroma ever undergoes malignant transformation [19]. In our cases, there was no recurrence of any lesion over a long-term follow-up of about 15 years.

These tumours may exhibit variations in their neoplastic behaviour; it is therefore important to take into account the individual tumour behaviour when one is planning the proper surgical treatment, in order to eliminate the tumour completely, avoid tumour recurrence, and at the same time improve the patient’s cosmetic and functional problems [7].

In conclusion, to distinguish between ossifying fibroma and other fibro-osseous lesions is the primary diagnostic challenge. COF shows wider areas of representation in the craniomaxillofacial region. The clinical and radiographic findings are varied. Its definitive diagnosis depends upon histopathological features. Enucleation and curettage are restricted to smaller lesions. However, complete excision of the lesion gives satisfactory outcome to prevent its recurrence and hence can be considered as definitive treatment modality. Long-term follow-up is required to evaluate recurrences.

Abbreviations

COF

Cemento-ossifying fibroma

OF

Ossifying fibroma

CT

Computed tomography

Compliance with Ethical Standards

Informed Consent

Patients in the study have given informed consent to participate in the study.