Artículo Clínico

---

Clinical, radiological and histological analysis of the cemento-ossifying fibromas of the maxilla
Análisis clínico, radiológico e histológico de los 
fibromas cemento-osificantes de los maxilares*

 

L. Domínguez Cuadrado¹, R. Martín-Granizo López²

---

Abstract: Introduction. The COF is a benign fibro-osseous neoplasm, more frequent in females on their 3rd and 4th decades of life, of non-odontogenic origin, that is preferentially localised on the molar and premolar mandibular area. Objective. The objective of this study is to analyse the clinical, radiographic and histologic features of cemento-ossifying fibromas (COF) and its controversial classification. To evaluate the fibro-osseous lesions from which a differential diagnosis is mandatory for a proper treatment. Patients and method. A retrospective clinical study has been made from year 1999 to year 2000 of 10 patients with COF, analysing the age, sex, personal antecedents, symptoms, localisation and radiographic and histologic characteristics of such lesions. In all the patients a local excision of the tumour was performed, as well as a minimum follow-up of six months after surgery, using radiologic controls. Results. Of all the patients studied, 7 were females and 3 males, with an age between 26 and 70 year-old. In the majority of the cases the lesion was placed in the posterior mandibular segment and was asymptomatic. On clinical examination the most common finding was a swelling of the bony cortex. Radiologically there was a mixed patron (radiolucid-radiopaque) which corresponded in the histologic analysis to a fibrous stroma with calcified trabecular and spherical deposits resembling to bone and cementum. Definite treatment included a local excision of the lesion followed by a simple curettage of the wound, with no evidence of recurrence during the follow-up. Conclusions. The COF is a benign fibro-osseous neoplasm, of non-odontogenic origin, that is preferentially localised on the molar and premolar mandibular area. It uses to be asymptomatic and radiographically it shows as a well defined lesion, with a mixed patron, without apical involvement. A differential diagnosis must be made with other fibro-osseous lesions, based on the exploration, histology, and radiologic study. Its treatment must be conservative, being the recurrences very uncommon. Key words: Cemento-ossifying fibroma; Cementifying fibroma; Non odontogenic tumour; Maxillary tumour; Mixed patron.

Resumen: Introducción. El fibroma cemento-osificante (FCO) en una neoplasia fibro-ósea benigna, de estirpe no odontogénica, más frecuente en mujeres entre la 3ª y 4ª décadas de la vida y que se localiza preferentemente en la región molar o premolar mandibular.  Objetivos. Analizar las características clínicas, radiológicas e histológicas del fibroma cemento-osificante (FCO) y su controvertida clasificación. Evaluar las lesiones fibro-óseas con las que es necesario realizar un diagnóstico diferencial para llevar a cabo un tratamiento adecuado. Material y método. Se ha realizado un estudio retrospectivo durante el periodo de 1999-2002 de 10 pacientes con FCO, valorando la edad, sexo, antecedentes personales, sintomatología, localización y características radiográficas e histológicas de la lesión. En todos los pacientes se realizó una extirpación local del tumor y un seguimiento mínimo de seis meses tras la cirugía con controles clínicos y radiográficos. Resultados. De los pacientes estudiados 7 eran mujeres y 3 varones, con edades comprendidas entre los 26 y 70 años. En la mayoría de los casos la lesión estaba localizada en el sector posterior mandibular y era asintomática. En la exploración física el hallazgo más frecuente fue un abombamiento de la cortical ósea. Radiológicamente se evidenciaba un patron mixto (radiolúcido-radiopaco) que en el análisis histológico correspondía a un estroma fibroso con depósitos calcificados trabeculares y/o esferoidales que recordaban respectivamente al hueso y/o cemento. El tratamiento definitivo consistió en la extirpación local de la lesión y curetaje, sin observarse ninguna recidiva durante el periodo de seguimiento. Conclusión. El FCO suele ser una lesión asintomática que radiográficamente se presenta como una lesión delimitada, de patrón mixto (radiolúcido-radiopaco), que no afecta a los ápices dentarios. Debe realizarse un diagnóstico diferencial con otras lesiones fibro-óseas basado en la clínica, la histológía y el análisis radiográfico. Su tratamiento es conservador, siendo raras las recidivas. Palabras clave: Fibroma cemento-osificante; Fibroma cementificante; Tumor no-odontogénico; Tumor maxilar; Patrón mixto.

---

1 Médico Residente
2 Médico adjunto
Servicio de Cirugía Oral y Maxilofacial (Jefe de Servicio: Dr. A. Berguer) 
Hospital Clínico San Carlos. Madrid, España.

Correspondencia:
Dr. Rafael Martín-Granizo López
Servicio de Cirugía Oral y Maxilofacial. Hospital Clínico San Carlos
C/ Profesor Martín Lagos s/n. 28040 Madrid, España.
e-mail: rmartin.hcsc@salud.madrid.org.

*Premio de la SECOM, Dr. Gómez Iglesias del año 2003.

 

Introduction

Maxillary bones have some special characteristics that make them favorable to suffer a large variety of lesions. They are membraneous ossification bones (with compact and spongy bone tissue similar to the rest of the skeleton), they have teeth and thus the rest of the embryonic tissues that they are formed from. They are lined by the gingival mucosa and may contain heterotropic remains of salivary glandular tissue. All this leads to the fact that we can find cysts, odontogenic tumors, non-odontogenic tumors and pseudotumoral lesions in this location. The osteofibrous tumors of the head and neck were first described as pathologic entities by Lichtenstein more than 60 years ago.^{1, 2}

The cemento-ossifying fibroma (COF) is a fibro-osseous neoplasm having a mesodermic origin that originated from multipotential cells of the peridontal ligament and form a part of these lesions. However, given their clinical, radiological and histological characteristics, their classification has been and is very controversial.³

The objective of this present study is to analyze the clinical, radiological and histological characteristics of the COF, stressing the radiological appearance of its different development phases, its classification and the different fibro-osseous lesions, so a differential diagnosis must be performed to carry out an adequate treatment.

Material and method

A retrospective study was performed of the COF cases diagnosed in our Service during the period of 1999-2002, considering age, gender, background and symptoms of the patients as well as the radiographic and histologic study of the lesions (Table 1). We found ten patients, seven women and three men whose ages ranged from 26 to 70 years (Fig. 1).

In three of the patients, there was underlying periodontal disease, two others had a previous traumatic background (exodontia of a third molar and of a molar one year before and two months before the diagnosis of the lesion, respectively) and an ameloblastoma extracted 7 years before in one of the women. In all the patients an OPG was performed and a CT was done in those in whom there was an intraosseous lesion greater than 10 mm (6 cases).

All the lesions, except one located in the upper maxilla, were found in the mandible, specifically in its molar and premolar area (Fig. 2 and  3).

An excisional biopsy was performed in eight of the patients, excising the lesion and performing a curretage of the residual cavity. An incisional biopsy and then a final treatment with complete extraction of the lesion were carried out only in patients who presented a verrucous tumor of the mucosa. The surgical treatment was performed under general anesthesia in 7 patients (due to the extension and location of the lesion) and with local anesthesia in the remaining three. The residual cavity was not filled with any material in any other cases. 

Results

Macroscopically, the resected tumors had a lobulated appearance, with a hard consistency on palpation. In the histological analysis, a stroma of the fibrous connective tissue with vascular canal, bone trabeculas and/or small coalescent calcified spherical foci was observed. No mitosis or cellular atypias were observed (Fig. 4). 

A minimum follow-up of 6 months was performed in all the patients, with control OPG at,1, 3 and 6 months post-surgery. No relapse was detected and adequate ossification of the residual bone defects was observed in the ten patients (Fig. 5, 6, 7 and 8).

Discussion

Since 1972 and after the modification performed by Schajowicz,⁴ the WHO considered cementing fibroma and ossifying fibroma as different entities, the first belonging to the group of tumors of odontogenic lineage and the second to the tumors of non-odontogenic lineage. Only an adequate histologic analysis permits both pathologies to be differentiated, it being considered a cementing fibroma if cement deposits are found in the fibrous stoma. In 1992, the WHO modified the classification of the maxillary lesions, including cementing fibroma and ossifying fibroma under the COF denomination and including them within the group of non-odontogenic lineage tumors.^5,6 However, this terminology and new classification is not universally accepted, since it ignores the appearance of cement deposits in the fibro-osseous lesions of other parts of the body. 

The present study is going to be based on this last classification of 1992, thus defining the COF as a benign neoplasm that is osteogenic (non-odontogenic), well defined and rarely encapsulated, consisting of fibrous tissue with variable amounts of mineralized material similar to bone and/or cement.

It is a fibro-osseous lesion that is relatively rare and, according to Eversole et al.,⁷ that typically affects women (5:1) between the 3rd and 4th decades of life, with a predilection for the molar (52%) and premolar (25%) area of the inferior maxilla, as occurs in 9 of the cases studied. Although the maxilla, zygoma, and even ethmoids, frontal bone and petromastoid region may also be affected by this lesion, the COF was located in the upper maxilla in only one of the cases analyzed. Different authors coincide in stating that the COF of the middle facial line and paranasal sinuses have a more aggressive behavior than those having a mandibular location.^{8, 9} In spite of the fact that it is an intraosseous lesion, cases affecting the gum and soft tissues have been described.¹⁰ In our study, we have found two patients in whom the gum was clearly affected and an excrescent, ulcerated, painful, friable lesion that bled when touched could be observed. 

Clinically, COF is generally asymptomatic (being frequently detected casually), although in long evolution cases, a growing facial asymmetry (generally unpainful) can be caused due to bone cortical curvature. 

The radiological appearance of this lesion varies greatly, apparently depending on the stage of its development. On occasions, a well defined uni- or multilocular radiolucent area and in other cases, a radiolucent area that is also circumscribed with different grades of radiopacity inside are detected. For some authors, this lesion is surrounded by a fibrous capsule, this appearance being very important for the differential diagnosis of fibrous dysplasia.¹¹ Other authors, however, admit that it is a circumscribed lesion, with a clear radiolucent halo, but that it does not correspond in any way to a capsule but rather to a transition between dysplasic tissue and healthy bone.¹² There has also been speculation on the origin of the different radiodensities of its inside, some stating that it is a madurative process according to which, the older the lesion, the greater the radiopaque areas presented.¹³ According to our experience, the smaller lesions and thus those having less evolution time, hardly presented radiopacities inside and the largest COF have a mixed pattern that is predominantly radiopaque, which would support this theory. Reabsorption or displacement of the adjacent dental roots is rare, but it can appear in large sized or long evolution lesions.

The etiologic factor is not clear, but it has been related with inflammatory processes (periodontitis), exodontias and traumatic backgrounds.^14,15 In the patients examined, periodontal disease appears as a background on three occasions and exodontia of a third molar in another. The patient who was operated due to an ameloblastoma years earlier presented the COF on the opposite side of the mandible, so that we do not consider it a predisposing factor.

In the histological study, a fibrous stroma made up of fusiform cells that are mixed with calcified trabecular and/or spherical foci that resemble, respectively, bone and cementum, is observed. It has a moderate vascularization (with occasional erythrocytic extravasation), mitotic activities or atypias is rare, giant cells (generally located in the center of the stroma) can be found^16,17 and in some zones, there is an acute inflammatory infiltrate with multiple polymorphnuclears. COF has a slow but constant growth, so that it must be excised. For some, the amount of cementum existing in the COF is directly related with its more aggressive behavior.¹³ This fact has been confirmed in the cases that we have detected in our study; the larger COF with more aggressive behavior presented a greater amount of cementum in their stroma. Generally, and as demonstrated by our experience, a conservative treatment, enucleating the lesion, is sufficient, relapses being very rare.

Thus, a careful clinical history and examination, detailed radiologic analysis and above all, correct pathology examination aimed at performing an adequate differential diagnosis are necessary.^16,17 The fibro-osseous lesions that must be ruled out to carry out the diagnosis of cemento-ossifying fibroma are:¹⁸

Fibrous dysplasia. It is a benign and progressive fibro-osseous lesion in which the normal bone tissue is substituted by fibrous tissues with fasciculated or frankly bone areas. It can be mono- or polyostotic according to whether it affects one or several bones. In the polyostotic form, there are cutaneous and/or endocrine alterations. The dysplasia of the maxillas is almost always monostotic. It is more frequent in women and asymmetry is generally produced in the maxillas due to expansion of the painless alveolar bone. Radiologically, a mixed pattern (radiolucent-radiopaque) and poorly defined lesion is observed, which constitutes the main radiological sign for the differential diagnosis with COF.

Focal cemento-osseous dysplasia (Fig. 9). As with the COF, it is more frequent in women, in the lower maxilla and is asymptomatic. In the radiological examination, a radiopaque zones is seen (that does not alternate with radiolucent areas), having well defined borders, that may be connected with the dental apex. The pathological study shows a fibrous tissue with minimum lymphocytic infiltration and masses of cementum, pseudo-osteoid tissue and bone damage.

Juvenile COF. Contrary to COF, it generally appears in patients under 15 years of age, predominating in the upper maxilla and with rapid growth that frequently erodes the surrounding bone tissues. The histological picture is characterized by a cellular-vascular stoma with variable amount of giant cells, scarce collagen and small ossicles surrounded by an osteoid halo.

Osteoid osteoma. It is more frequent in persons under 30 years of age and in males, rare in the maxilla (typically found in the femur, tibia or phalanx). It causes pain that predominantly occurs during night time which gives good orientation for its differential diagnosis with other bone lesions and it appears as a well circumscribed radiolucent area with sclerotic halo on the X-ray.

Osteoblastoma. It is preferentially in the spine (rarely in the mandible), causes pain and the radiological image varies greatly but is generally poorly defined (in the COF, the lesion is typically well defined) and with erosion of the cortical bone.

Benign cementoblastoma. More frequent in those under 20 years of age, generally located in the mandibular molar region and closely associated with dental apices. Pain and expansion of the cortical bone are characteristic symptoms and signs.

Ameloblastic fibroodontoma. Above all, it affects young individuals and the mandibular angle region. A circumscribed lesion surrounded by a sclerotic halo with a radiopaque focus is observed in the radiographic analysis. Histologically, they are lobulated tumors surrounded by a fibrous capsule and formed by mixoid connective tissue with cords of odontogenic epithelium that possess cells still in process of differentiation that produce dentin and enamel.

Cementoblastoma. It appears in the second and third decade of life, more frequently in the posterior mandibular region. It is always associated with dental roots and frequently causes its reabsorption. Radiologically, it is an opaque lesion with a radiolucent halo and the histological study reveals a conglomerate of material similar to cementum and connective tissue. Many of the cemental trabeculae are surrounded by cementoblasts in activity.

Osteomyelitis. The pain, inflammation and involvement of the general condition orients towards an inflammatory condition of this type.

Osteosarcoma. It is a primary malignant bone tumor of rapid progression that causes pain, sensory disorders, limitation of mandibular mobility and displacement or mobility of dental pieces. Rhizolysis and involvement of the cortical bone is frequently observed in the X-ray.

Conclusions

The COF is a rare entity, with controversial classification that is presently considered to belong to non-odontogenic tumors. It most frequently affects women between 30 and 40 years of age and is basically located in the posterior region of the mandible. It is generally asymptomatic and has a variable radiological appearance, based on evolution time and development phase. It is always a circumscribed lesion and the mixed pattern (in which radiolucent areas alternate with other radiopaque ones) is characteristic of lesions in advanced stages. The histology shows a fibrous connective stroma with trabecular and coalescent calcified spherical foci. Its behavior is benign and local excision of the lesion is sufficient.

Acknowledgements

To the pathologists, Drs Luis Ortega (Madrid), and Conchita Alvarez-Cañas and Antonio González-Fernández Carreño (Leon) for their help in the histological analysis of the cases.

References

1. Lichtenstein I. Polyostotic fibrous dysplasia of bone. Arch Surg 1938;36:874-98.         [ Links ]

2. Lichtenstein, Jaffe HL. Fibrous dysplasia of bone. Arch Pathol 1942;33:777-816.         [ Links ]

3. Waldron CA. Bone Pathology. Neville BW, Damm DD, Allen CM, Bouquot JE. Oral Maxillofac Pathol. WB Saunders Co. Philadelphia 1995:443-92.         [ Links ]

4. Schajowicz F. Tumores y lesiones pseudotumorales de huesos y articulaciones. Madrid. Panamericana 1982.         [ Links ]

5. Waldrom CA. Fibro-osseous lesions of the jaws. J Oral Maxillofac Surg 1993;51:828-35.         [ Links ]

6. De Vicente JC, González S, Santamaría J, Madrigal B. Non odontogenic tumours of the jaws: classification, behavoir and diagnosis. Med Oral 1997;2:83.         [ Links ]

7. Eversole LR, Leider AS, Nelson K. Ossifying fibroma: a clinicopathologic study of 64 cases. Oral Surg Oral Med Oral Pathol 1985;60:505-11.         [ Links ]

8. Cox VS, Rimmel FL, Marenttete LI, Ness JA. Ethmoidal cemento-ossifying fibroma: the transglabellar/ subcranial approach. Otolaryngol Head Neck Surg 1996; 114:335-8.         [ Links ]

9. Saito K, Fukuta K, Takahashi M, y col. Benign fibroosseous lesions involving the skull base, paranasal sinuses and nasal cavity. J Neurosurg 1998;88:1116-9.         [ Links ]

10. Manganaro AM, Ragno JR, Karlis V. Mixed radiolucent/radiopaque lesion of the mandible. J Oral Maxillofac Surg 1997;55:1456-9.         [ Links ]

11. Su L, Weathers DR, Waldrom CA. Distinguishing features of focal cemento-osseous dysplasias and cemento-ossifying fibromas. A pathologic spectrum of 316 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 84:301-9.         [ Links ]

12. Lello GE, Sparro OC. Craniofacial poliostotic fibrous displasia. J Oral Maxilofacial Surg 1985;13:267-72.         [ Links ]

13. Hammer JE, Scofield HH, Cornyn J. Benign fibro-osseous jaw lesions of periodontal membrane origin: an analysis of 249 cases. Cancer 1968;22:861-8.         [ Links ]

14. Regezi JA, Sciubba J. Oral Pathology: Clinical- Pathologic Correlations. 2ª ed. Philadelphia. WB: Saunders Co, 1993:383.         [ Links ]

15. Alandez J, Herrer JI, Sanz M, Carasol M. Mandibular cementifyng fibroma in relation a large periodontal bone defect. Report of a case. J Periodontol 1995;66:291        [ Links ]

16. Kramer JRH, Pindborg JJ, Shear H. Histological Ttyping of Odontogenic Tumours. 2ª ed. Springer-Verlag, Berlin 1997.         [ Links ]

17. Lucas RB. Pathology of Tumours of the Oral Tissues. Edimburg: Livinstone 1984:402-5        [ Links ]

18. Martín-Granizo R, Sánchez Cuellar A, Falahat F. Cemento-ossifying fibroma of the upper gingivae. Otolaryngol Head Neck Surg 2000;122:775.         [ Links ]