Multicentric peripheral ossifying fibroma: A case report and review of the literature.

A peripheral cement-ossifying fibroma is a benign fibro-osseous lesion of a reactive rather than a neoplastic nature, whose pathogenesis is uncertain. It predominantly affects adolescents and young adults, with the peak prevalence between 10 and 19 years, especially affecting females (two to four times more). Such lesions are commonly found on the maxillary bone. We hereby present and discuss a unique case of multicentric Peripheral Ossifying Fibroma (POF) affecting both the maxillary and the mandibular gingiva in an 11-year-old boy, with a disease duration of two months. This case is probably one of the first few cases discovered, which demonstrates that there may be a multicentric variant of the Peripheral Ossifying Fibroma. The purpose of this article is to present a case of POF and to briefly review the current literature on this condition.

INTRODUCTION

The peripheral ossifying fibroma (POF) accounts for 3.1% of all oral tumors[1] and for 9.6% of all gingival lesions.[2] In 1872, Menzel first described the ossifying fibroma, but only in 1927, did Montgomery assign its terminology.[3] The literature reports a great incidence in infants and in young adults, mainly in the age range of 10 to 19 years,[4] mainly affecting females (two to four times more),[5] suggesting some hormonal influences as well.[1]

The pathogenesis of this tumor is uncertain; however, the pluripotent cells of the periodontal ligament have the apparent ability to transform or metaplastically change into osteoblasts, cementoblasts or fibroblasts, in response to irritants such as calculus, bacterial plaque, orthodontic appliances, ill-adapted crowns, and irregular restorations, and are therefore, capable of producing a unique inflammatory hyperplasia, the peripheral ossifying fibroma.[1678910] The cells of the periosteum or periodontal ligament also synthesize the mineralized product of this entity.

The POF, representing a reactive benign lesion of the connective tissue, is not the soft tissue counterpart of the central ossifying fibroma, which represents an osteogenic neoplasm.[11] The central type of ossifying fibroma arises from the endosteum or the periodontal ligament (PDL) adjacent to the root apex and expands from the medullary cavity of the bone. On the other hand, the peripheral type shows a contiguous relationship with the PDL, occurring solely on the soft tissues overlying the alveolar process.

Clinically POF presents as a solitary, slow-growing, and well-demarcated nodular mass that exhibits a smooth surface, usually with normal-colored mucosa. It has a sessile or pedunculated base and is generally of a hard consistency.[12] Such lesions are generally smaller than 1.5 cm in diameter,[13] although there have been reports of some large 4 cm lesions as well.[14] About 60% of such lesions occur in the maxilla and more than 50% of all cases affect the region of the incisors and canines; more precisely in the interdental papilla.[4131415]

In the vast majority of cases, there is no apparent underlying bone involvement visible on the roentgenogram. However, on rare occasions, there does appear to be superficial erosion of the bone. A possibility of tooth migration due to the presence of a peripheral cemento-ossifying fibroma has been reported.[16] The lesions must be surgically excised and microscopically examined for confirmation of diagnosis. The extraction of the adjacent teeth is seldom necessary. However, the lesions do occur with some frequency, and in fact, repeated recurrences are not uncommon.

Clinical differential diagnosis for such gingival growths includes fibroma, peripheral giant cell granuloma, pyogenic granuloma, peripheral odontogenic fibroma, and peripheral ossifying fibroma.[17]

Thus, the definitive diagnosis of POF is made by the histological evaluation of a biopsy specimen.[6] We hereby report a unique case of a multicentric variant of POF, wherein, the patient presents with multiple lesions of POF on the maxillary and mandibular gingiva, and it is among the few multicentric variants of POF reported in literature.

CASE REPORT

A healthy 11-year-old boy presented to the Postgraduate Department of Periodontics and Oral Implantology, with ‘slow-growing, painless, soft tissue masses in the maxillary posterior regions bilaterally’ that enlarged gradually for two months. The lesions started as small papules one year back. According to the patient, the lesions had been present for approximately two months and his mother stated that it had just recently become visible between the teeth [Figures 1 and 2]. Totally there were approximately five lesions, three in the maxilla and two in the mandible. In the mandible, the lesions were present between the lower right first premolar and deciduous first molar and on the left side between the deciduous first and second molar. As reported by the patient, the lumps were interfering with his bite and felt uncomfortable. Occasionally, bleeding occurred when he brushed his teeth.

Figure 1

Multiple oral lesions of peripheral ossifying fibroma in both the maxilla as well as the mandible

Figure 2

Occlusal clinical view of the lesions showing their expansile nature

The lesions initially occurred on one side of the mouth and in a subsequent course of time involved both sides. Both the maxillary and mandibular gingivae were affected and the growths appeared as nodular masses, with erythematous and ulcerated surfaces. The growths were sessile and firm in consistency measuring anywhere between 5 mm and 3 cm in diameter. The lesions appeared reddish-pink in color and were slightly pedunculated, with what appeared to be a broad-based attachment. The lesions were not fluctuant, nor did they blanch with pressure, but had a rubbery consistency. The lesions were tender to firm pressure, but not to light palpation.

Radiographic examination

Panoramic radiographs were obtained [Figure 3]. The radiographs did not reveal any abnormality and there was no finding pertaining to the multiple exophytic lesions.

Figure 3

Orthopantogram of a patient showing mixed stage of dentition, without any abnormality pertaining to the multiple exophytic lesions

Biochemical investigations

The laboratory tests performed included, a complete blood hemogram and lipid and thyroid profiles. All the test results were within normal limits except for the total leukocyte count, which was slightly more than normal (12800/mm3 of blood).

Histopathological examination

On histopathological examination, upon low power magnification (4x), the lesional tissue exhibited a keratinized stratified squamous epithelium (gingiva), overlying a fibrous connective tissue stroma exhibiting dense interlacing bundles of collagen and numerous ossifications [Figure 4]. High power magnification (40x) showed pink homogenous calcified tissue (ossification), with a presence of osteocytes entrapped in the lacunae [Figure 5]. The histology for all the lesions was the same. The picture is consistent with the clinical diagnosis of POF.

Figure 4

Histopathological examination of the lesional tissue at ×4 magnification

Figure 5

Histopathological examination of the lesional tissue at ×40 magnification

Treatment

Under local anesthesia, the lumps were excised completely using a scalpel. The tissue was submitted to the Oral Pathology Division for histopathological diagnosis. The deciduous teeth present in the lesion were also removed and included in the biopsy specimen. The adjacent teeth were scaled to remove any local irritants.

Follow-up

The patient presented for a follow-up examination 20 days postoperatively. The surgical site appeared to be healing well [Figures 6 and 7]. There was no evidence of recurrence of the lesion and the child was asymptomatic.

Figure 6

Post treatment photograph

Figure 7

Post treatment photograph revealing complete healing of the lesions

DISCUSSION

Intraoral ossifying fibromas have been described in literature since the late 1940s. Many names have been given to similar lesions, such as, epulis, peripheral fibromas with calcification, peripheral ossifying fibromas, calcifying fibroblastic granuloma, peripheral cementifying fibroma, peripheral fibroma with cementogenesis, and peripheral cemento-ossifying fibroma.[3618192021] The varied nomenclature used for fibroblastic gingival lesions indicates that there is much controversy surrounding the classification of these lesions.[622]

The main etiological factors of POF are trauma and chronic irritation, particularly from the subgingival plaque and calculus.[35823] Eversole and Rovin[3] stated that the constant irritation present during exfoliation of the deciduous teeth and eruption of the permanent teeth may also result in an increased incidence of reactive lesions, which originate from the periodontal ligament. This hypothesis is based on the fact that POFs arise exclusively on the gingiva, the subsequent proximity of the gingiva to the periodontal ligament, and the inverse correlation between age distribution of patients presenting with POF and the number of missing teeth with associated periodontal ligament.[123] Despite reports of POF in children with deciduous or mixed dentition, little data is available regarding the specific occurrence of this lesion, with involvement of the deciduous dentition. The literature also reflects the association of natal teeth with the peripheral ossifying fibroma.[24] Defective odontogenesis and/or retarded eruption of teeth have also been found to be associated with similar histological features in the dental follicles.[25]

In order to reach some conclusion about the diverse etiology of this condition, a concise review of literature was conducted and tabulated in Table 1.

Table 1

Comprehensive review of literature regarding the etiology and clinical presentation of peripheral ossifying fibroma

Ossifying fibromas may be clinically and radiographically impossible to separate from cementifying fibromas.[26] Much of the research study has been carried out to distinguish ossifying fibromas from cementifying fibromas, by using immunohistochemical analysis for keratin sulfate and chondroitin-4 sulfate, in which the cementifying fibromas show significant immunoreactivity for keratin sulfate and the ossifying fibromas show intensive immunostaining for chondroitin-4 sulfate.[27]

Such lesions may be present for a number of months to years before excision, depending on the degree of ulceration, discomfort, and interference with function.[418]

CONCLUSION

A peripheral cement-ossifying fibroma is a slowly progressing lesion, the growth of which is generally limited. Many cases will progress for long periods before patients seek treatment, because of the lack of symptoms associated with the lesion. Treatment consists of surgical excision, including the periosteum and scaling of the adjacent teeth. Close postoperative follow-up is required because of the growth potential of incompletely removed lesions and an 8 - 20% recurrence rate.

The recovery of the current patient was uneventful and the patient has remained tumor-free for about one-and-a-half years. As the recurrence rate of this tumor is fairly high, the patient is still on regular follow up.