Overview

Gums in your mouth are known to have frequent inflammatory lesions. Peripheral ossifying fibroma (POF)¹ is an infrequent lesion that occurs exclusively on your gums. POF is an inflammatory reactive hyperplasia of gingiva. Ossifying means changing into bone, and fibroma refers to the fibrous tissue that makes up the tumour. 

POF infrequently occurs, usually on the interdental papilla, in response to trauma or irritation. POF arises from peripheral tissues3 like gingiva, accounting for 9.6% of gingival lesions.¹

POF has also been described by various synonyms such as peripheral cemento-ossifying fibroma, peripheral fibroma with osteogenesis, peripheral fibroma with calcification, fibrous epulis, peripheral odontogenic fibroma with cementogenesis, and calcifying fibroblastic granuloma.¹

Causes of peripheral ossifying fibroma

• The causes of POF are unclear, an origin from periodontal ligament is suggested since POF exclusively occurs in the gingiva, the proximity of gingiva to the periodontal ligament and the presence of oxytalan fibers within some lesions¹
• Poor oral hygiene is a predisposing factor of peripheral ossifying fibroma
• The main causative factors in POF consist of chronic irritation and trauma
• Dental calculus, plaque, microorganisms¹, food lodgement, dental appliances, masticatory force, ill-fitting crowns, ill-fitting dentures, inadequate restorations and use of orthodontic devices² are considered to be the irritants triggering the lesion
• Eversole and Rovin stated that constant irritation during the exfoliation of deciduous teeth and eruption of permanent teeth may result in reactive lesions 

Who gets the disease

• POF may occur at various ages, but exhibits a peak incidence between the second and third decade with the peak prevalence between the ages of 10 and 19 years⁴
• Only 0.5% cases are reported in older age group
• Whites (71%) are more frequently affected than blacks (36%)⁴
• Most commonly seen in females due to the hormonal influences²
• Maxilla is the most common site for POF compared to mandible with a predilection for the anterior maxilla and it mostly occur anterior to molar teeth³

Signs and symptoms

• POF is a painless reactive soft tissue growth most often located in the gingival papilla between the teeth
• The lesion though usually smaller than 1.5 cm (ranges from 0.4 to 4.0 cm) in diameter can reach a much larger size
• POF may be broad based, sessile or pedunculated
• Usually smooth surfaced pink lobulated mass
• Cauliflower-like rubbery mass
• POF can cause separation of the adjacent teeth, destruction of the bony structure, resorption of the alveolar crest, and cosmetic deformity
• Pale pink to cherry red in color¹

POF in children

• POF is fast growing and reach significant size in a relatively short period of time in children
• POF can displace teeth, or can cause delayed eruption of teeth
• POF can cause erosion of bone in children

Diagnosis

• Early diagnosis and conservative management is important, since they can become more destructive over time

Histopathological examination

Histopathologic evaluation of biopsy specimens is the confirmatory diagnosis done for POF. Features observed during the microscopic examination are:⁴

• Intact or ulcerated stratified squamous surface epithelium
• Cementum-like material and dystrophic calcifications are more prevalent in ulcerated lesions
• Non-cancerous fibrous connective tissue with varying numbers of fibroblasts
• Sparse to profuse endothelial proliferation
• Mature mineralized material
• Collagen and myofibroblast
• Woven or lamellar osteoid, dystrophic calcifications or cementum-like material is present in mineralised material
• Acute or chronic inflammatory cells in lesions
• Osteoblastic rimming within collagen tissue is visible
• Lamellar or woven osteoid pattern predominates in histopathological examination; hence, the term “POF” is considered more appropriate.
• The calcified material can generally take one or more of the four forms:¹
  • immature, highly cellular bone
  • circumscribed amorphous, almost acellular, basophilic or eosinophilic bodies
  • mature lamellated trabecular bone
  • minute microscopic granular foci of calcification

In POF, squamous epithelium can be ulcerated or intact. Three zones can be found in the ulcerated lesion:¹

Zone I: Superficial ulcerated zone

• It is covered with the fibrinous exudate
• Polymorphonuclear neutrophils and debris are seen in this zone

Zone II: Zone beneath the surface squamous epithelium

• It is composed of proliferating fibroblasts
• Chronic inflammatory cells (lymphocytes and plasma cells) can be seen

Zone III: More collagenized connective tissue.

• This zone shows high cellularity and less vascularity

Except for the presence of surface epithelium, non-ulcerated lesions are identical to ulcerated. 

Radiographic features

• Radiographic features of POF may vary
• Radiopaque foci of calcifications are found scattered in the central area of the lesion
• Not all lesions demonstrate radiographic calcifications¹
• Superficial erosion of bone is noted in rare cases

Differential diagnosis

POF has to be differentiated from other reactive lesions of gingiva, like irritation fibroma pyogenic granuloma, peripheral giant cell granuloma (PGCG) and peripheral odontogenic fibroma.

Pyogenic granuloma presents as an erythematous overgrowth³ with surface ulceration. It has a tendency to easily bleed clinically. Microscopically it exhibits vascular proliferation resembling granulation tissue. 

PGCG can be differentiated by histological appearance, which shows scattered giant cells in a fibrous stroma

Peripheral odontogenic fibroma shows prominent islands of odontogenic epithelium in the histological picture. Though not significant in most of the cases, some alterations in bones are noted, like foci of calcifications, bony erosion, widening of the periodontal ligament space, and thickened lamina dura. Alteration in teeth position due to interdental bone loss is also seen

Treatment

Removal of irritants

Scaling and root planing of adjacent teeth and/or removal of sources of irritants should be performed to avoid recurrence

Surgical excision by scalpel, laser or radial/electrosurgery

Surgical excision including the involved periodontal ligament and periosteum is the preferred treatment.

The chances of high recurrence (8–20%) for POFs indicate that a careful treatment strategy should be recommended, involving the excision of the entire lesion.

Excision involves removing the ligament and periosteum at the base of the lesion in order to reduce the chances of recurrence.

Carbon dioxide laser 

• Carbon dioxide laser can excise the lesion effectively⁴
• This laser helps to obtain biopsy sample with minimal distortion and helps for microscopic evaluation 

Advantages of carbon dioxide laser excision

• Minimal post-surgical pain and there is no need for suturing 

Limitations of carbon dioxide laser excision

• Carbon dioxide laser can also result in partial or incomplete or partial removal of the base of the pathologic lesion,
• Incomplete removal of lesion can lead to recurrence and hence surgical excision is the preferred treatment

FAQs

Where is the most common site for peripheral ossifying fibroma?

Maxilla is the most common site for POF. POF is mainly seen in the anterior maxilla anterior to molar teeth

How do you treat peripheral ossifying fibroma?

Surgical excision after removing local triggering or causative factors like dental calculus, plaque, microorganisms, food lodgement, dental appliances, masticatory force, ill-fitting crowns, ill-fitting dentures, and inadequate restorations.

Surgical excision of the lesion involving the periodontal ligament and periosteum at the base of the lesion is the most preferred treatment for POF. Since POF has high recurrence rates, complete excision of the lesion is mandatory.

Is peripheral ossifying fibroma malignant?

Peripheral ossifying fibroma is a non-malignant entity that occurs on the gingiva in response to irritation or trauma. POF occurs exclusively on the gingiva.

What is a peripheral ossifying fibroma classified as?

POF arises from periodontal ligament cells and is classified as reactive hyperplasia.

What is the size of a peripheral ossifying fibroma?

POF lesions are usually smaller than 1.5 cm (ranges from 0.4 to 4.0 cm) in diameter and can reach a much larger size. POF is fast growing and reaches a significant size in a relatively short period of time in children.

What is the difference between peripheral ossifying fibroma and peripheral giant cell granuloma?

Peripheral ossifying fibroma and peripheral giant cell granuloma occur on gingiva and are unique to the oral cavity.

But unlike POF, peripheral giant cell granuloma can occur on the alveolar mucosa of edentulous areas.⁵

Summary

POF is a painless, slowly progressive lesion with limited growth.POF occurs exclusively on gthe ingiva. POF appears as a smooth lobulated mass. This lesion is present mainly in 10-19 years of age. The lesion appears pale pink to cherry red in color. POF has female predilection due to hormonal influences. The cause of the lesion is unclear. Triggering factors include dental calculus, plaque, microorganisms, food lodgement, dental appliances, ill-fitting crowns, restorations and use of orthodontic device. 

POF is difficult to diagnose, so histopathologic confirmation is mandatory. On histological examination, fibroblasts and lamellar or osteoid pattern can be seen. Complete surgical excision down to the periosteum is the preferred treatment as the recurrence rate is high (8-20%).