Although benign tumours are not inherently fatal, they can turn malignant, posing significant morbidity on the afflicted patients if left untreated. When a lesion is growing in the body, it undergoes enlargement enough to begin pressing down and compressing the structures and organs. One such category of tumour is known as Juvenile ossifying fibroma (JOF) - a rare lesion that is usually benign, pertaining to the craniofacial region in children and young adults.¹ This article covers what exactly JOF is including its aetiology, clinical features, epidemiology, radiographic characteristics, differential diagnosis, and management strategies. 

Introduction

Juvenile ossifying fibroma (JOF) is a rare condition usually characterised by the presence of a benign fibro-osseous neoplasm, afflicting children under the age of 15 years. Usually occurring more commonly in the maxilla - bones present in the upper part of the mouth - than in the mandible - bones present in the lower jaw of the face. This lesion has hichanceces of recurring and re-presenting itself, with asymptomatic symptoms, it proceeds to grow and due to its aggressive nature arises suspicions of appearing malignant.²

Figure 1. and 2. Maxilla of the skull. and Mandible of the skull (respectively)^8,9

What exactly is an ossifying fibroma?

Ossifying, as defined by the Oxford dictionary, means turning into bone or bony tissue and a fibroma is a benign fibrous tumour of connective tissue. Therefore, an ossifying fibroma is a benign, non-cancerous tumour that comprises tissue of the bone that forms within the connective tissue. Neoplasm, the abnormal growth of a tissue, in the jaw classified by the replacement of regular bone tissue with mineralised fibrous tissues and newly formed calcified products, either cementum or bones or both [3]. 

According to the World Health Organisation (WHO, 1992) an ossifying fibroma is a “demarcated or rarely encapsulated neoplasm consisting of fibrous tissue containing varying amounts of mineralised material resembling bone and/or cementum”.⁴

Who is affected by this?

JOF affects mainly children and adolescents under the age of 15, with an average ranging around the ages of 8-12 years. Only about 20% of the patients are older than the age of 15 at the age of onset of this disease. There is a slightly high occurrence of JOF in males in comparison with females, presenting itself in a ratio of 1.5:1.

JOF can be classified as trabecular (TrJOF) or psammomatoid (PsJOF), based on their histological subtypes.⁵

TrJOF is a condition that affects bones in the upper jaw (maxilla rather than the mandible). Patients are usually around the age of 2-12 years at the age of onset.

PsJOF is a condition that usually occurs in the bones of the eyes and nose (periorbital or sinus bones), with an age of onset around 3-72 years of age.

Hence, TrJOF is a more common form of ossifying fibroma in juveniles in comparison to PsJOF.⁶ JOF is a rare occurrence, accounting for about 2-6% of all of the fibro-osseous lesions within the craniofacial bones.

What is juvenile ossifying fibroma caused by?

The exact origin of JOF is currently unknown. Most cases occur at a young age, sporadically without any family history or pre-dispositions of this particular condition. 

The most commonly agreed-on hypothesis is that some of the aggressive behaviour and growth of the tumour in JOF could be driven due to a mutation in a gene on chromosome 12. This pathogenic change in the gene variant causes an amplification in genes, such as RASAL1 and MDM2. 

Some of the common stimuli are misfitted crowns or fillings, dental calculus or plaque. 

• Any sort of maladapted filling or prosthetic, arising from the proliferation or growth of peripheral cells from the gums. 
• Mostly affects the regions anterior of the mouth, such as the canines, incisors, and maxilla. 
• Presenting due to the presence of irritant stimuli.

Mainly occurring due to:

• Gum irritation,
• Trauma to the jaw or face,
• Build-up of dental plaque, or
• Dental procedures.

Signs and symptoms of juvenile ossifying fibroma

Most patients’ symptoms are asymptomatic, and the fibraoma only becomes more pertinent and obvious once a large lesion mass has been formed and eventually discovered on a dental X-ray. 

On the rare occasion that the symptoms are symptomatic, there are symptoms that are not-so-specific - depending on the bones in the affected areas, -like:

• Rhinorrhea (runny nose)
• Chronic sinusitis
• Nasal obstruction
• Epistaxis (nosebleeds)
• Possible visual changes
• Facial asymmetry and enlargement
• Paresthesia (loss of motor control and sensation in the face)
• Tooth loss or exfoliation
• Bulging of the eyes (proptosis)
• Ptosis (eyelid drooping)
• Optic disc bulging (Difficulty with eye movement)
• Malocclusion (unaligned teeth)
• Pus discharge

The two main symptoms pertaining to JOF are nasal congestion and bulging of the eyes and facial swelling.⁷ Malignant tumours tend to destroy the surrounding tissues, but benign ossifying fibromas have a tendency to expand the bones in the affected region. 

Certain disorders present with similar features of JOF

Disorders such as:

• Cementoblastoma
• Gnathic cemento-ossifying fibroma
• Familial ossifying fibroma
• Extracranial meningioma
• Osteoma
• Fibrous dysplasia of the bone

How can you identify juvenile ossifying fibromas?

Mainly detected in radiological screenings like routine dental X-rays, where it presents itself as a homogenous, well-defined lesion with a clear radiopaque (white) border. However, this could depend on the size and stage at which the lesion is occurring. Some X-rays can be radiopaque and radiolucent (black) upon maturation, or entirely radiolucent. 

After an x-ray is taken that depicts signs of JOF, a more detailed imaging scan is performed. For example, magnetic resonance imaging or a computer tomography scan. That delves deeper into the origin, size, and precise localisation of the lesion. 

An ear-nose-throat doctor (ENT) or maxillofacial surgeon is consulted as well. 

A biopsy is then taken of the tumour in order to come to a definitive diagnosis and conclude the prevalence of a JOF. A pathologist is able to pinpoint the specific morphological changes of the fibroma biopsy taken under a microscope. 

Histologically, when viewed by a pathologist, JOF is characterised by the presence of various bones - cementum, trabecular, and woven - in a conglomeration of fibrous stroma. The fibrous stroma is embedded in a matrix consisting of collagen composed of spindle-shaped fibroblasts. 

How can you treat juvenile ossifying fibroma?

Upon detection of the fibroma and confirmation through a biopsy, an endodontist removes the ossifying fibroma in the juvenile surgically. If the tumour needs removal, a bone graft might be needed to replace the bone that was extracted. 

The fibroma must be completely removed in order to with a large clear margin in order to avoid recurrence since chances of the fibroma reappearing are quite common - about 80%.

When removed with a larger margin, the recurrence rate is reduced to about 0-4%. 

Untreated fibromas can become large and overtake the position of the healthy bone. This increases the chances of an individual being affected with a facial fracture. Fibromas, or other such tumours can also lead to the reabsorption of the roots of your teeth, leading your teeth to be misplaced and move. 

When should I contact the doctor?

When a child presents symptoms like:

• Facial swelling or pain
• Red bumps on gums
• Irritated gums
• Chronic nasal congestion

How to manage and subside Juvenile Ossifying Fibroma?

Overall, patients with JOF lead relatively normal lives. Once detected and removed, followed with routine checkups in order to track the progress of the tumour, since recurrence is quite common. 

Summary

Juvenile ossifying benign fibromas are rarely occurring tumour lesions that tend to affect the maxilla-mandible area, as well as the sinus regions. Juvenile, meaning occurring in children and adolescents prior to the age of 15, affects the bones in the craniofacial regions. Ossifying fibroma is a condition when the rudimentary bone tissue becomes fibrous and more mineralised in the connective tissues. Although benign, like most other tumours, can become malignant if untreated and left to grow and expand further. Very rarely does it spread to other parts of the body and metastasise. Usually asymptomatic, diagnosed during routine dental x-rays, which can further be verified using CT and MRI scans, and confirmed by a biopsy. Removal of the lesion via a large clear margin in order to avoid recurrence and regular follow-up checks are advised.