Ossifying Fibroma of Non-odontogenic Origin: A Fibro-osseous Lesion in the Craniofacial Skeleton to be (Re-)considered

Abstract

In the cranio-facial skeleton, a heterogeneous group of well characterized fibro-osseous lesions can be distinguished. Whereas fibrous dysplasia can affect any skeletal bone, ossifying fibroma and cemento-osseous dysplasia exclusively develop in the cranio-facial region, with most subtypes restricted to the tooth bearing areas of the jaws. Herein we present a series of 20 fibro-osseous lesions that developed mostly in the frontal bone and in the mandible, presenting as expansile intramedullary tumors with a unique histologic appearance and an indolent clinical course. We provide evidence that these tumors are distinct from the categories included in the WHO classification and are therefore currently unclassifiable. The definition of cemento-ossifying fibroma as an odontogenic neoplasm developing only in close proximity to teeth should be re-considered and incorporate also extragnathic lesions as shown here.

Clinical management of cementifying fibroma: A case report and pertinent review of the current literature

“…COF was therefore relocated into the benign mesenchymal odontogenic tumors category. It was also defined as a distinct type of ossifying fibroma that occurs in the tooth-bearing areas of the jaws and is believed to be of odontogenic origin [1,5]. Nevertheless, the acronym COF was used throughout the relevant section on ossifying fibroma except for juvenile ossifying fibroma (JOF) variants: juvenile trabecular ossifying fibroma and juvenile psammomatoid ossifying fibroma [1].…”

“…Nevertheless, the acronym COF was used throughout the relevant section on ossifying fibroma except for juvenile ossifying fibroma (JOF) variants: juvenile trabecular ossifying fibroma and juvenile psammomatoid ossifying fibroma [1]. Therefore, there is a proposal to reconsider conventional ossifying fibroma as comprising odontogenic and non-odontogenic subtypes because of several extragnathic cases reported [5].…”

“…A COF is generally a spherical or egg-shaped, slowly expanding mass that affects the teeth-bearing areas, resulting in root resorption of varying degrees on adjacent teeth. Although the origin of COF is still debated, it is considered that traumatic injuries or local irritants are possible reasons for their occurrence [5]. In the present study, we discuss the case of a 23-year-old male who was referred to the oral surgery department just before he was about to be conscripted into the military.…”

Update of Key Clinical, Histological and Molecular Features of Malignant Bone Tumours Arising in the Craniofacial Skeleton

“…Distinguishing between low-grade OS and benign fibro-osseous lesions of the jaws, particularly craniofacial fibrous dysplasia, and sometimes cemento-ossifying fibroma, can be challenging, especially if the corresponding imaging is not available and/or the biopsy material is limited. We have recently described a new variant of ossifying fibroma occurring also outside of the jaws (ossifying fibroma of non-odontogenic origin) that can be another differential diagnosis to consider ( 21 ). However, osteosarcoma usually shows a more aggressive growth pattern on imaging and entrapment of host bone is never seen in benign fibro-osseous lesions, therefore representing a distinctive morphological feature.…”

Direct evidence supporting a periodontal ligament origin for central cemento‐ossifying fibroma

“…Traditionally, the PDL, which is part of the odontogenic apparatus, has been proposed as the histogenetic source of central COsF based primarily on clinical observations of its confinement to tooth-bearing areas. [2][3][4][5] Nevertheless, one should bear in mind that radiological or pathological evidence to support this hypothesis has so far been unavailable in the existing literature, 2 as COsFs typically occur as sizable intraosseous lesions. Here, we provide conclusive evidence of a PDL origin for central COsF by presenting a unique exophytic-type lesion that developed on the lateral surface of the tooth root.…”