Florid osseous dysplasia.

The concept of 'fibro-osseous lesions' of bone has evolved over the last several decades and now includes two major entities, viz., fibrous dysplasia and ossifying fibroma, as well as other less common entities such as periapical dysplasia, focal osseous dysplasia, florid osseous dysplasia and familial gigantiform cementoma. Florid osseous dysplasia is a central lesion of the bone and periodontium, which has caused considerable controversy because of confusion regarding terminology and criteria for diagnosis. This paper reports a rare case of florid osseous dysplasia affecting maxilla and mandible bilaterally in a 14-year-old Indian male patient.

INTRODUCTION

Florid osseous dysplasia (FOD) is a very rare fibro-osseous condition presenting in the jaws. The term florid is used because of its widespread and extensive manifestation; this lesion also appears to be a reasonably well defined clinical and radiological entity that deserves a separate category.[12] In the past, this condition has been designated as multiple cemento-ossifying fibromas, sclerosing osteitis, sclerosing osteomyelitis, multiple enostosis, multiple osteomas, periapical cementoblastoma, Paget's disease of the mandible, gigantiform cementoma, chronic sclerosing osteomyelitis, sclerotic cemental masses of the jaws, and multiple periapical osteofibromatosis.[1-4]

Osseous dysplasias (ODs) are idiopathic processes located in the periapical region of the tooth-bearing jaw areas, characterized by replacement of normal bone with fibrous tissue and metaplastic bone. They are non-neoplastic bone lesions and are considered to originate from the periodontal ligament.

FOD is a type of osseous dysplasia which is more extensive, occurs bilaterally in the mandible or may even involve all four quadrants.[5] It mainly occurs in middle-aged black females, with the patients usually being free of symptoms except when the disease is complicated by chronic osteomyelitis.[5-7]

This paper reports an unusual case of florid osseous dysplasia in a 14-year-old Indian male patient, which is rare with regard to this race, age and sex.

CASE REPORT

A 14-year-old Indian male patient presented with a slowly enlarging hard swelling on the left side of the face since one month [Figure 1]. The patient was asymptomatic, with no history of trauma or pain.

Figure 1

Clinical photograph showing minimal swelling on lower right side of the face

Intraoral examination revealed a diffuse hard swelling involving mandibular body. The swelling was seen extending bilaterally from premolar region to anterior border of ramus with slight buccal cortical plate expansion. All teeth present in the oral cavity were vital.

An orthopantogram displayed diffuse, lobular, irregularly shaped radiopacities involving the maxilla and mandible. These radiopaque masses were observed solely in the tooth-bearing alveolar areas and appeared to be unattached to the root apices [Figure 2].

Figure 2

Orthopantogram shows irregular radiopaque globular masses symmetrically involving all four quadrants

CT scan confirmed the presence of mixed-density, expansile lesion with areas of sclerosis and ground-glass attenuation involving bilateral maxilla (extending into the maxillary sinuses), body and rami of mandible. The lesion consisted of dense lobulated masses with indistinct radiolucent borders [Figures 3 and 4[. Systemic skeletal radiographs indicated that the lesions were limited to jaw.

Figure 3

Coronal CT scan showing extensive mixed radiopaque and radiolucent lesions involving both the maxilla and mandible

Figure 4

Axial CT scan showing sclerotic masses causing bilateral bicortical expansion of mandible

Three-phase bone scan was done with 10 mCi of 99 mTc - Methylene disphosphonate (MDP) injected IV and blood pool images were taken immediately. Static images were taken three hours later. Increased radiotracer uptake was seen in the body of mandible and both the maxillae with increased vascularity on blood pool images [Figure 5]. Rest of the skeleton showed unremarkable tracer uptake.

Figure 5

Three-phase bone scan (99 mTc) showing increased radiotracer uptake in the body of mandible and maxilla

The results of blood chemistry of the patient were within normal limits.

An incisional biopsy was taken from the right mandibular premolar area. The histopathological findings showed cellular fibrous tissue interspersed with woven as well as lamellar bone and masses of cementum-like material. Irregular and rounded deposits of metaplastically formed cementum-like material had dark basophilic boundaries and seemed to fuse, creating large globular masses. In some areas, spindle-shaped fibroblasts were arranged in swirling pattern around small mineralized deposits [Figure 6].

Figure 6

Photomicrograph showing cellular fibrous stroma interspersed with globular cementum-like masses (short arrow) and bone trabeculae (long arrow) H and E stain (10×)

All clinical, radiographic, biochemical and histopathological features were suggestive of the diagnosis of florid osseous dysplasia. No treatment was rendered, and the patient was kept under observation. At the two-year follow-up, the patient was asymptomatic with insignificant clinical and radiographic alterations.

DISCUSSION

Melrose and co-workers coined the term florid osseous dysplasia (FOD) to describe an exuberant multiquadrant fibro-osseous or fibrocemental process of the jaws. These lesions were characterized by dense sclerotic masses, often interpreted as cementum,[8] although they referred to them as osseous dysplasia because cementum was considered to be indistinguishable from bone.[79]

The terms cemental and osseous were used interchangeably because lamina dura and cementum develop in association with the periodontal membrane. Therefore, the term cemento-osseous dysplasia was proposed by WHO (World Health Organization), in conjunction with Waldron and co-workers.[10]

The confusion about how to define and classify these lesions is reflected by the plethora of terms that have been used to describe the lesion. The term osseous dysplasia has been re-introduced in the new classification of head and neck tumors given by WHO (July 2005), thus pooling the different entities under one heading.[511]

FOD may have jaw bone changes similar to those of familial gigantiform cementoma (FGC), another type of osseous dysplasia (OD),[5] making the differential diagnosis difficult. However, FGC is characterized by multiquadrant expansile lesions typically affecting both jaws, often crossing midline, thereby producing asymmetry and facial disfigurement. It presents as an autosomal dominant trait, most frequently affecting during childhood, with no apparent gender and racial predilection. Also, the behavior of this lesion is more akin to neoplasia, necessitating surgery, which is otherwise contraindicated for the largely asymptomatic FOD.[451012-14]

Although in our case the age of the patient is comparable to that of the patient of familial gigantiform cementoma, our case had a different clinical presentation, being much less aggressive and having no history of any familial involvement.

Other lesions which must also be considered in the differential diagnosis are Gardner's syndrome, Paget's disease and chronic diffuse sclerosing osteomyelitis. Unlike Gardner's syndrome,[15] FOD has no other skeletal changes, skin tumors or dental anomalies.[16] Paget's disease is polyostotic and shows a pathognomic increase in serum alkaline phosphatase levels.[1517]

Chronic diffuse sclerosing osteomyelitis is a frequent complication of FOD, although it can also present as a primary condition of the mandible characterized by cyclic episodes of unilateral pain and swelling and is not always confined to tooth-bearing areas.[1315]

The cause of FOD is unknown, and there is no good explanation for its gender and racial predilections. Waldron et al. have proposed that reactive or dysplastic changes in the periodontal ligament might be a cause for the disease.[3]

Asymptomatic patients of florid osseous dysplasia generally do not require treatment, unless complications occur. Surgical intervention such as a remodeling resection is reserved for cases with gross disfigurement. Complete resection of the lesion is considered to be impractical because the lesion usually occupies most of the mandible and maxilla. In the reported case, the patient was asymptomatic and aesthetics were not disturbed. Hence we decided to abstain from surgery and kept the patient under observation and regular follow-up.[451315]