# Extraosseous Cemento-Ossifying Fibroma of the Cheek

Authors: Gianluigi Longobardi; Immacolata Pagano; Umberto Sisalli; Maurizio Foresti; Valentina Poddi
Journal: Scholarly Research Exchange
 (2009)

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## Abstract

Background. Cemento-ossifying fibroma (COF) is a relatively rare tumor of the maxillary bones, classified among the fibro-osseous lesions Feller et al. (2004). The lesion that develops appears within the bone, although in some cases, it involves the soft tissues  Kaufmann et al. (1999), Jung et al. (1999). In literature there is not report of COF in the thickness of the cheek. Methods. A 24-year-old Caucasian woman presented a hard mass of 1.5 cm in the thickness of the right cheek; no signs of damaged tissues were present. Radiographically all the mass appeared radiopaque as bone, and well demarcated with an evident capsule, without invasing the adjacent structures. The lesion was resected en bloc. Result. Pathological examination of the excised mass revealed an encapsulated cemento-ossifying fibroma that did not invade the adjacent tissues. The case was resolved with no complicance and with restitutio ad integrum. Conclusion. Typically, the unusual characterisitcs of a pathology get difficult as for its diagnosis and therapy. This is a case report of a rare cemento-ossifying fibroma of the cheek. Clinical and instrumental examinations exclude a malignant pathology and lead to an appropriate conservative surgical therapy. Only the histological examination confirmed the clinical diagnosis of extraosseous COF.


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## Body

## 1. Introduction

The Ossifying Fibroma (OF) is a benign tumor of
the maxillary bones [1].It is a relatively rare lesion, considered as
an osteogenic tumor (nonodontogenic) with variable expressiveness. Clinically
it is defined as a well-demarcated and occasionally encapsulated lesion.The histopathology consists in a fibrous tissue
that may vary in cellularity from areas with closely packed cells to nearly
acellular parts within the same lesion. The mineralized component may consist
of woven bone, lamellar bone, and acellular to poorly cellular basophilic, and
smoothly contoured deposits thought to be cementum [2].Because of these characteristics, the WHO
(2005) defines the OF and cemento-ossifying fibroma (COF) synonyms [3].There are two histologic variants of OF that
are the Juvenile trabecular ossifying fibroma (JTOF) and the juvenile
psammomatoid ossifying fibroma (JPOF). The juvenile ossifying fibroma instead
represents an active/aggressive form.To start explaining the nature of COF and its
mineralized component like cementum, it was supposed to have origin from the
periodontal membrane, therefore, with double embryonic origin (ectodermic and
mesodermic). In fact connective tissue of the periodontal membrane can
contemporarily elaborate both bone and cementum. But the localization of COF
out of the maxillary bones, like skull and extracranial sites, has given rise
to discussions regarding the real nature of cement nature in the calcification.Bernier hypothesized that the ethiopathogenesis
of the COF in the bone might be caused by an irritant stimulus (such as tooth
extraction) which may activate the production of new tissue from the remaining
periodontal membranes [4].The ethiopathogenesis of the COF in the
extraosseous forms where there is no periodontal tissue is discussed. Çakir and
Karadayi [5] suggested that extraosseous COF originated from embryologic nests
while Brademann et al. explained that ectopic periodontal membrane was the
origin of the COF [6].In the end the WHO (2005) defined cementum as a
mineralized material covering the rooths surface of the teeth and outside this
location, its distinction from bone is equivocal and out of clinical
relevance [3].Usually this lesion occurs in the mandibular
molar or premolar regions although in some occasions it involves extra jaws
bones and the soft tissues [5, 7–10].In the current literature, there have been
reports of some cases with cemento-ossifying fibroma (COF) involving the nose,
the orbit, the ethmoid, maxillar and sphenoid sinuses, the occipital and the
temporal bones, and nasopharynx [7, 8, 11–14].In the present work, the authors present a rare
case of COF located in the thickness of the cheek, which represented a
difficult initial diagnosis because of its unusual localization.


## 2. Case History

A 24-year-old Caucasian woman was referred to
have a mass growing in the thickness of her right cheek, located in the region
of the angle of the mandible (Gonion), five months before coming to the
authors’ clinic.During the clinical observation, the face
appeared asymmetric for the presence of a painless mass. The mucous and the
external skin did not show signs of lesions. The dimensions were around 2 cm in
diameter.The palpation performed in rest and in
clenching of the teeth by the patient showed a hard consistent lesion close to
the massetere muscle but not adherent to it, and on the tissues around it;
these appeared soft and easily palpable. No latero-cervical lynphoadenopathy
was present. No clinical pathology was observed in the anamnesis; there were no
traumatic events or allergies. The patient performed an X-ray of the chest, an
arch dental radiography, and a TAC of the face.The TAC report carried a 1.5-cm oval
formation-like bone-radio density with clean and regular borders (Figures1, 2).
The formation is independent of the bone of the mandible.Figure 1
CT image.Figure 2
Surgical time.The X-Ray of the chest was negative.The patient was submitted to surgical therapy
under local anesthesia by intra oral access.The lesion was easily dissected from the
surrounding tissue. It was a bony-like tissue covered by a thin layer of soft
tissue.There were no complications after surgery.


## 3. Histopathology

### 3.1. Macroscopic Findings

The specimen consisted of a large, hard solid
mass measuring1.5×1.7×1.4 cm.This tissue had a spherical-ellipsoidal form;
its colour was white-gray and was not completely covered by a soft tissue
capsule.


### 3.2. Microscopic Findings

A well-circumscribed and half-encapsulated
fibro-osseous lesion has an abundant cellular fibrous tissue with scattered
trabeculae of lamellar bone. No cellular atipies and dental tissues were
present.The morphological pattern is compatible with
the ossifying fibroma (Figure3).Figure 3
(original x25) Whorls of
fibrous tissue and calcified material (cementum).


## 3.1. Macroscopic Findings

The specimen consisted of a large, hard solid
mass measuring1.5×1.7×1.4 cm.This tissue had a spherical-ellipsoidal form;
its colour was white-gray and was not completely covered by a soft tissue
capsule.


## 3.2. Microscopic Findings

A well-circumscribed and half-encapsulated
fibro-osseous lesion has an abundant cellular fibrous tissue with scattered
trabeculae of lamellar bone. No cellular atipies and dental tissues were
present.The morphological pattern is compatible with
the ossifying fibroma (Figure3).Figure 3
(original x25) Whorls of
fibrous tissue and calcified material (cementum).


## 4. Discussion and Conclusions

The clinical comparison of the extraosseous
forms of COF is rare.In 1999, Kaufmann et al. described
a case of COF in a 22-year-old man, situated in the right ear auricle dx [7],
while in the same year Jung introduced a case of COF in the parapharyngeal and
masticatory spaces [8].Subsequently, Keefe et al. (2000) and
Galdeano Arenas et al. (2004) reported two different cases of COF in the gingival
region [9, 10].More cases were observed in the skull and other
bones out of the jaws such as frontal bone, nasal cavity, ethmoid, sphenoid
orbit, and mastoidea region [6, 11, 13, 15].In the light of literature reports, the
unusual localization of COF in the case reported does not let us imagine about
its nature.Even if clinic and rx exams were comfortable to
exclude a malignant lesion, we had doubts about the real nature of the lesion.Different diagnoses are often done to the
following pathologies:(1)
Myositis ossificans: this is a benign
process characterized histologically by a central fibroblastic tissue with an
intermediate zone with trabeculae and a peripheral zone of calcification and
mature lamellar bone.(2)
Well-differentiated osteosarcoma: this is
characterized by lack of atypical nuclear in the spindle cells.(3)
Fibrous dysplaisa: this is characterized by
a woven bone arising directly from the fibrous tissue, without osteoblastic
activity.(4)
Odontogenic lesion (odontogenic fibroma,
ameloblastic fibroma, ameloblastic fibro-sarcoma, ameloblastic
fibro-odonto-sarcoma): this is characterized by the presence of dental
epithelial structures as an integral tumor component.
The therapy is surgical in the form of a
complete resection of the lesion. Since it is low vascularized and
well circumscribed, it is easy to remove it from the surrounding bone.We could obtain a definitive diagnosis only
through the histological exam.Prognosis was excellent, and the patient got the
restitution ad integrum of the lesion.This experience allows us to consider less in
doubt this kind of lesions.



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*Source: 493190-2009-04-22.xml*