In this article, we describe a patient with FCOD with an overlying CDO to illustrate the alteration of normal radiographic appearance. We also review the differential diagnoses.

	CASE REPORT

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A 61-year-old African woman reported to the oral and maxillofacial radiology clinic at the University of Medicine and Dentistry of New Jersey’s (UMDNJ’s) New Jersey Dental School, Newark, with a chief complaint of chronic pain in the mandible that had lasted approximately five years. She had immigrated to the United States less than a year before and arrived at the dental school with her daughter, who acted as her interpreter. Two of us (S.R.S. and M.M.) performed a clinical examination to determine her radiographic needs, and we noted that the patient had multiple missing teeth. The remaining teeth had carious lesions and failing restorations. The bite appeared to be collapsed, and several of the teeth appeared to be occluding with the opposing residual ridge. Several areas of suppuration were visible at the crest of the residual mandibular ridge (Figure 1). The entire mandible was tender to palpation. Copies of intraoral radiographs, taken at another dental office in New Jersey, were not of diagnostic quality. Since the patient could not contact her previous dentist in Africa, we decided to take new radiographs. A panoramic film was indicated for the initial survey.

View larger version (87K): [in this window] [in a new window]   Figure 1. Intraoral photograph of the patient showing the traumatized mandibular ridge with areas of suppuration.

View larger version (88K): [in this window] [in a new window]   Figure 2. Panoramic radiograph of patient. The sclerotic bone extends beyond the mandibular canal inferiorly to the border of the mandible and posteriorly and bilaterally into the ramus.

– The inferior alveolar canal was widened.

– Sclerotic bone extended to both angles of the mandible and from the inferior border of the mandible to the level of the inferior alveolar canal.

– The inferior cortex was obliterated.

– There was no notable expansion of the mandible.

– The borders of the lesion were indistinct and blended into the unaffected surrounding bone.

– In the right body of the mandible, inferior to the inferior alveolar canal and superior to the inferior border of the mandible, was a well-demarcated radiolucency.

– Superior to the canal were islands of well-demarcated, irregularly shaped radiopaque masses of varying density, extending to the crest of the alveolar ridge. These masses were confined to the mandibular toothbearing alveolar bone. In some areas, there were radiolucent gaps between the radiopacities.

– The maxillary ridge contained bilateral radiopacities that were consistent with FCOD.

The two treating clinicians referred the patient to the oral and maxillofacial surgery (OMFS) service of the UMDNJ New Jersey Dental School for evaluation and treatment. OMFS staff obtained computerized tomographic imaging of the patient. Figure 3 shows the axial computerized tomographic (CT) scan of the lesion. Radiographic results revealed the following:

View larger version (80K): [in this window] [in a new window]   Figure 3. Axial computerized tomographic scan of mandible in bone window. Note the sequestra and the sclerotic bone.

– sclerosis of the inferior border of the mandible;

– perforation of the buccal plate of bone;

– cemental tissue or bony sequestra.

OMFS clinicians débrided the mandible and submitted specimens (Figure 4) for biopsy. In addition, they cultured the lesion for microbiological workup. Treatment options for the osteomyelitis included hyperbaric oxygen,³ saucerization and autogenous bone grafting,⁴ and the use of gentamicin-impregnated poly-methymethacrylate beads.⁵

View larger version (124K): [in this window] [in a new window]   Figure 4. Surgical specimen. Only the infected cemento-osseous tissue, including the sequestra, was excised.

View larger version (112K): [in this window] [in a new window]   Figure 5. Photomicrograph of the biopsy specimen (hematoxylin and eosin stain, x 40 magnification).

	DISCUSSION

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Fibro-osseous lesions are a group of disorders of bone in which normal bone is replaced with fibrous connective tissue containing abnormal bone or cementum. Included in this group are FCOD, fibrous dysplasia and periapical cemental dysplasia (PCD).⁶ The initial radiographic appearance of this group of lesions is radiolucent. Over time, the lesions progress to a mixed radiolucent-radiopaque stage before progressing to a completely radiopaque stage. The normal trabecular pattern of bone is not seen within the lesion. Each lesion has its characteristic textures, a fact that can aid in the differential diagnosis.

Florid cemento-osseous dysplasia. FCOD is a benign fibro-osseous lesion in which mature bone is replaced with woven bone in a matrix of fibrous connective tissue.^7,8 Typically, this condition affects middle-aged women and has a predilection for people of African and Asian descent.⁶ The lesions often are bilateral and have a symmetrical appearance. The borders are round to lobulated in shape² and vary from well-defined to poorly defined. It is common to see a radiolucent rim surrounding the lesions. The radiographic appearance can vary from areas of lucency to mixed lesions and to rather opaque masses. Over time, the lesions tend to become increasingly radiopaque.^7,9 The lesions can be found in multiple quadrants in both the maxilla and the mandible.^6,7 Generally, they are confined to the toothbearing regions.² FCOD occasionally is expansile, and patients with it may report experiencing pain.⁶

Fibrous dysplasia. Fibrous dysplasia is one of the benign fibro-osseous lesions that can affect the jaws. It tends to occur during the second decade of life. It is generally painless, unless it impinges on structures such as canals. Lesions of fibrous dysplasia tend to stop growing after puberty is reached.^10,11 Unique to fibrous dysplasia are the superior displacement of the mandibular canal and the various patterns of trabeculation, such as orange peel, ground glass and thumb whorl.¹ The trabeculations appear different on the radiograph than those of the FCOD, owing to their smaller size and peculiar shape. The borders of such lesions tend to be diffuse, blending in with the surrounding unaffected bone.

Periapical cemental dysplasia. Fibro-osseous lesions confined to the anterior mandible, within the space between the canines, are considered a separate but related disease termed PCD.⁶ While the lesions in PCD generally are painless, the patient occasionally may complain of poorly localized pain, especially if a simple bone cyst has developed within the lesion. Although the lucent area in the lower right body of the mandible appears to continue with the radiolucent zone surrounding the FCOD, it also may represent a simple bone cyst.¹² There may be some localized bone swelling, but usually no treatment is indicated.⁶ Over time, with the loss of teeth and the residual alveolar bone, the cemento-osseous masses may emerge through the overlying mucosa, leaving the area susceptible to osteomyelitis.¹³ The resulting infection may be caused by direct communication through the mucosa or merely by trauma to the overlying tissues. The osseous masses are avascular and susceptible to bacterial overgrowth.² Differential diagnoses include CDO, Paget’s disease of bone and osteosarcoma.^3,14,15

Chronic diffuse osteomyelitis typically is found in the mandibular body, angle and ramus. Generally, it is unilateral.

Chronic diffuse osteomyelitis. CDO, an infection of intermedullary bone, may arise from a localized osteitis, previous acute osteomyelitis or prior infective processes.^6,9 Jacobsson¹⁶ extensively reviewed and described the clinical features, diagnosis and treatment of CDO. The infection tends to occur more frequently in developing nations.¹⁷ It is caused by the mutualistic relationship of the Actinomyces species with Eikenella corrodens. Patients with disorders resulting in decreased vascularity, patients who are immuno-compromised and patients with chronic systemic diseases tend to be susceptible to osteomyelitis. In addition, osteopetrosis, Paget’s disease of bone and FCOD result in decreased vascularity of the affected bone, predisposing it to the development of osteomyelitis.¹⁷

CDO typically is found in the mandibular body, angle and ramus.^9,18 Generally, it is unilateral, but in the patient described here, it affected both sides of the mandible.^2,16 CDO usually is longstanding, with episodes of soft tissue swelling, pain, fever and lymphadenopathy. The sclerotic bone results from increased osteoblastic activity. Radiographically, there is an alteration of the normal trabecular pattern.^19,20 The lesion demonstrates increased density and appears as an opaque segment of the mandible.² The borders are defined poorly, blending into the normal trabecular pattern. It usually is unilateral, though our patient’s radiograph showed involvement of the left and right sides. The lesion is not confined to toothbearing areas and may extend posteriorly to the ramus of the mandible. It can be differentiated from infected areas of FCOD by its spread beyond the toothbearing areas.²⁰ The mandibular canal may be widened.⁹ Sequestra may be present, as well as new periosteal bone formation. These are considered to be distinguishing features for CDO when fibrous dysplasia is considered as a differential diagnosis.¹ In addition, CDO may spread to the zygomatic arch and temporal bone.¹⁶ CT, in bone the window, is useful for viewing sequestra.

Differential diagnosis of the lesions includes fibrous dysplasia, Paget’s disease of bone, osteosarcoma and FCOD. More remote possibilities include Gardner’s syndrome and cemento-ossifying fibroma. All of these entities have some similar radiographic characteristics. Clinical examination and patient data may be crucial in differentiating the lesions.^1,6,7 Gardner’s syndrome, which can include multiple enostoses, usually is associated with intestinal polyposis and is hereditary. Multiple osteomas frequently are associated with them.⁶ Radiographically and histologically, cemento-ossifying fibromas can have an internal architecture similar to that of fibrous dysplasia. These lesions tend to be more localized and expansile.⁶

Paget’s disease of bone. Paget’s disease of bone affects men more than women and whites more than blacks. It is rare in Africans. Most cases of Paget’s disease of bone are polyostotic and tend to be relatively asymptomatic. Pagetic bone often forms near the joints. Maxillary involvement is far more common than mandibular involvement. The involved bone tends to expand significantly. On the basis of the patient’s demographic status and the clinical features of her condition, we ruled out Paget’s disease of bone.

Osteosarcoma. Osteosarcoma can often be differentiated radiographically by its "sun-ray" or "sunburst" pattern found in newly deposited periosteal bone, lesions extending into soft tissue, destruction of lamina dura and widening of the periodontal ligament spaces.¹

	CONCLUSION

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Multiple, simultaneous pathological processes can yield an atypical radiographic appearance in routine dental radiographs such as full-mouth series or panoramic radiographs. The effects of the overlying inflammatory process on the primary fibro-osseous lesions can alter its radiographic features. In our patient, the primary, underlying FCOD had undergone changes that were radiographically discernible owing to the initial infection of the FCOD and the subsequent CDO. We noted characteristics unique to each process that allowed us to arrive at the differential diagnoses. Clinicians should be aware of the radiographic manifestation of such conditions and learn to recognize their appearance.