Ossifying fibroma of the jaws: Report of two cases and literature review

Summary

Ossifying fibromas are uncommon benign tumors of the craniofacial skeleton thought to originate from the periodontal ligament. Most are small and incidentally diagnosed with routine dental radiographs. With larger lesions, patients may complain of an abnormal bite or an enlarging mass. This tumor involves slow-evolving growth with deforming swelling generally arising in the mandible, with possible early tooth displacement. From the radiological perspective, more than 50% of the lesions exhibit an expansion of the jaws and 53% shows well-defined unilocular radiolucencies and 40% are mixed radiolucent-radiopaque lesions. The lesions exceptionally can be radiopaque. Ossifying fibroma presents several variant histopathological subtypes. The overlapping clinical and histopathological features of these subtypes have led to diagnostic dilemma and confusion. Complete excision of this tumor has become a necessity since it is notorious for recurrence. We present here two cases of ossifying fibroma of the jaws along with insight into the literature review.

Introduction

The term, fibro-osseous lesions, refers to a diverse process in which the normal bone architecture is replaced by fibroblasts and collagen fibers containing variable amounts of mineralized material. The term is not a specific diagnosis but only indicates a broad group of several entities. Although there is no completely satisfactory classification, it is generally accepted that benign fibro-osseous lesions in the oral and maxillofacial region can be divided into three categories including fibrous dysplasia, benign fibro-osseous neoplasms, and reactive (dysplastic) lesions.¹ In 1872, Menzel gave the first description of a variant of OF, calling it a cemento-ossifying fibroma, in a 35 year old woman with a long standing large tumor of the mandible.² In 1927, Montgomery³ first used the term OF, by which the lesion is currently known. The name has subsequently also been used by other authors.[4], [5], [6] Until 1948, it was believed that fibrous dysplasia and OF were either the same entity or variants of one same lesion.⁵ That year, Sherman and Sternberg⁷ published a detailed description of the clinical, radiological and histological characteristics of OF, and since then most researchers coincide in considering the two lesions to be different clinical entities.[5], [7], [8] A number of authors have suggested that ossifying and/or cementifying fibromas are benign fibro-osseous lesions originating in the periodontal ligament – as a result of which they would constitute histological variants of one same pathological process.[4], [9], [10] The lesions are designated differently, depending on the type of tissue identified.⁸ Thus, the term OF is used if the predominant component is bone, while cementifying fibroma is defined by the presence of curvilinear trabecular structures or spherical calcifications. In turn, lesions characterized by the presence of bone and cementum are referred to as cemento-ossifying fibroma. However, the terms OF and cementifying fibroma are merely academic designations.[5], [8]

Ossifying fibroma (OF) is a fibro-osseous lesion that arises from the periodontal membrane.⁴ The periodontal membrane is a layer of fibrous connective tissue surrounding the roots of the teeth. It contains multipotential cells that are capable of forming cementum, lamellar bone and fibrous tissue.[11], [12] OF is a destructive, deforming, benign tumor that can occur almost anywhere in the facial skeleton. This uncommon tumor can present a diagnostic dilemma for the clinician and the pathologist, owing to overlapping clinical and histomorphologic features. Many synonymous nomenclatures exist for a single entity and the controversy in classification and staging of the subtypes in the literature has added to the confusion. Hence, there is a need to highlight the points of controversy existing for this tumor so that they could be avoided through a consensus in future. Although central OF of the mandible are common, they are unusual in the maxilla.¹³ The tumor can produce sinus obstruction, infection, facial deformity, proptosis and intracranial complications, even though it can remain asymptomatic in the early stage. In general, this tumor is relatively slow-growing,[14], [15], [16], [17] as a result of which the overlying cortical bone layer and mucosa remain intact,¹⁸ and thus the tumor may be present for a number of years before a diagnosis is made. The treatment of OF consists of surgical excision with extended resection depending on the size and location of the lesion.[17], [19] We present herein two cases of central OF of the jaws with a literature review.