Peripheral Ossifying Fibroma



Quick Summary
Introduction
References
Photos



Clinical Features
Histopathology
Treatment
Prognosis

Nodular, nonhemorrhagic mass of mandibular
gingiva has separated adjacent teeth.

 

 

 

 


 

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Introduction

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In addition to the peripheral giant cell granuloma, mesenchymal cells of the periodontal ligament are capable of producing another unique inflammatory hyperplasia, the peripheral ossifying fibroma, also referred to as the peripheral cementifying fibroma, depending on whether or not bone or cementum is seen microscopically. The pluripotential cells of the ligament have the apparent ability to transform or metaplastically alter into osteoblasts, cementoblasts or fibroblasts. The reader is reminded that this is a reactive lesion, not the peripheral counterpart of the intraosseous neoplasm called central cemento-ossifying fibroma. Odontogenic lesions of the gingiva, moreover, may produce various calcified materials and are discussed elsewhere in this book.

By definition, the peripheral ossifying fibroma must be associated with gingival tissues, and the diagnosis cannot be used for lesions of other oral sites. The presence of teeth is not, however, required for the diagnosis, as periodontal ligament fibers remain within and above alveolar bone long after their associated teeth have been extracted. Shepherd first reported this entity as alveolar exostosis in 1844.

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Clinical Features

Peripheral ossifying fibroma presents as a painless, hemorrhagic and often lobulated mass of the gingiva or alveolar mucosa (Figures 1 & 2), perhaps with large areas of surface ulceration. Early lesions are quite irregular and red, but older lesions may have a smooth salmon pink surface and may be indistinguishable clinically from the more common irritation fibroma. Most lesions are 1-2 cm. in size, but some may slowly enlarge to more than 4 cm. Early growth is often alarmingly rapid.

A lesion may vary somewhat in size over time, depending on the amount of superficial inflammation and edema. While this tumor is typically diagnosed in teenagers and young adults, it may occur at any age, especially in individuals with poor oral hygiene. Radiographs may show irregular, scattered radiopacities in the lesion (Figure 3).

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Pathology and Differential Diagnosis

An aggregated submucosal proliferation of primitive oval and bipolar mesenchymal cells is the hallmark of peripheral ossifying fibroma. The lesion may be very cellular or may be somewhat fibrotic, but scattered throughout are islands and trabeculae of woven or lamellar bone, usually with abundant osteoblastic rimming (Figures 4 & 5). Metaplastic bone may also be seen. The calcified tissues may have the dark-staining, acellular, rounded appearance of cementum, in which case the term peripheral cementifying fibroma has traditionally been used (Figure 6). Many examples show an admixture of bone and cementum, i.e. peripheral ossifying/cementifying fibroma, and early lesions may contain only small ovoid areas of dystrophic calcification. While the lesional stroma is similar to that of peripheral giant cell granuloma, the erythrocyte extravasation of the latter lesion is not a feature of peripheral ossifying fibroma and osteoclast-like cells are quite rare.

The lesional nidus is not encapsulated but is rather well demarcated from the surrounding fibrovascular stroma. Surrounding tissues are often edematous, with neovascularity and variable numbers of chronic and acute inflammatory cells. By way of differential diagnosis the exuberant callus so common to the long bones is almost never found at the surface of jawbones, hence, is not a serious diagnostic distinction from peripheral ossifying fibroma. Some gingival masses, however, contain large areas of classic pyogenic granuloma, irritation fibroma or peripheral giant cell granuloma, as well as peripheral ossifying fibroma. In such cases the pathologist usually chooses for the appropriate diagnosis the lesional type that predominates. Also, individual cells must be carefully examined for dysplastic changes in order to rule out osteoblastic osteosarcoma or juxtacortical osteosarcoma, but frequent mitotic figures of normal configuration are acceptable for the benign diagnosis, especially in lesions found in children.

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Treatment and Prognosis

Conservative surgical excision must be followed by diligent curettage of the wound and root planing of adjacent teeth if recurrence is to be avoided. With simple removal the recurrence rate is greater than 20%. Malignant transformation has not been reported for this lesion.

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References (Chronologic Order)

Note: General references can be found by clicking on that topic to the left.

Shepherd SM. Alveolar exostosis. Am J Dent Sc 1844; 4:43-44.

Buchner A, Hansen LS. The histomorphologic spectrum of peripheral ossifying fibroma. Oral Surg Oral Med Oral Pathol 1987; 63:452-461.

Kenney JN, Kaugers GE, Abbey LM. Comparison between the peripheral ossifying fibroma and peripheral odontogenic fibroma. J Oral Maxillofac Surg 1989; 47:378-382.

Zain RB, Fei YJ. Fibrous lesions of the gingiva: a histopathologic analysis of 204 cases. Oral Surg Oral Med Oral Pathol 1990; 70:466-470.

Poon CK, Kwan PC, Chao SY. Giant peripheral ossifying fibroma of the maxilla - report of a case. J Oral Maxillofac Surg 1995; 53:695-698.

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Pictures

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