Year : 2010 | Volume
: 28 | Issue : 2 | Page : 126--129
Bilateral fibrous dysplasia of the mandible in a 7-year-old male patient-A rare case
VV Chandar1, Priya2, Amita2,
1 Reader, Department of Oral Medicine & Radiology, BV.U. Dental College And Hospital, Pune, Maharastra, India
2 Postgraduate student, Department of Oral Medicine & Radiology, BV.U. Dental College and Hospital, Pune, Maharastra, India
V V Chandar
Department of Oral Medicine & Radiology, BV.U. Dental College And Hospital, Pune, Maharastra
Fibrous dysplasia is a disturbance of bone metabolism that is classified as a benign fibro-osseous lesion. Fibrous connective tissue, containing abnormal bone, replaces normal bone. The etiology of fibrous dysplasia is unknown. The radiographic appearance of the irregularly shaped trabeculae aids in the differential diagnosis. Occurring most commonly in the second decade of life, the lesions of fibrous dysplasia can be surgically recontoured for esthetic or functional purposes once they become dormant. Here, we report a case of bilateral fibrous dysplasia in a 7 year old male patient and its diagnostic work-up.
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Chandar V V, Priya, Amita. Bilateral fibrous dysplasia of the mandible in a 7-year-old male patient-A rare case.J Indian Soc Pedod Prev Dent 2010;28:126-129
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Chandar V V, Priya, Amita. Bilateral fibrous dysplasia of the mandible in a 7-year-old male patient-A rare case. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2020 Mar 30 ];28:126-129
Available from: http://www.jisppd.com/text.asp?2010/28/2/126/66756
Fibrous dysplasia is a developmental anomaly in which normal bone is replaced with fibrous connective tissue. As the lesion matures, the fibrous connective tissue is replaced with irregularly patterned trabecular bone.  It is a localized abnormality that can involve one (monostotic) or multiple (polyostotic) bones. With initial development of fibrous dysplasia, the patient usually reports facial swellings and asymmetries. Although the lesion is usually asymptomatic, encroachment on canals and foramina, as well as limitations of movement, may engender complaints of pain and discomfort. , In general, males and females are thought to be affected evenly, although recent research has shown a slight female preponderance.  The lesions of fibrous dysplasia are twice as common as those in the maxilla as the mandible, and the posterior aspects of the jaw are more frequently affected than the anterior.
A 7-year-old male, accompanied by his parents, reported to Department of Oral Medicine and Radiology complaining of swelling on both right and left cheek regions since 2.5 years, which had gradually increased and hardened to attain the present size and consistency [Figure 1]. Extra-oral examination revealed uniform hard expansion on both the right and left lower jaws, extending up to inferior border of the right and left sides of the mandible. Intra-oral examination revealed obliteration of left vestibule and decreased depth of the right vestibule [Figure 2]. A clinical diagnosis of fibrous dysplasia of mandible was made. Further investigations revealed slight rise in erythrocyte sedimentation rate (ESR) and mild change in the alkaline phosphatase level which was approximately 564 units. Blood picture also revealed slight anemic state that was managed by advising balanced diet and medication. Conventional and advanced imaging investigations revealed diffuse increase in the attenuation of mandible, with loss of normal trabecular pattern leading to classical ground glass pattern. Mild expansion of mandible and upward displacement of mandibular canal were evident, especially in the left half of the mandible, giving an impression of fibrous dysplasia of mandible [Figure 3],[Figure 4],[Figure 5],[Figure 6]. Incisional biopsy of the lesion confirmed the clinical and radiographic diagnosis of fibrous dysplasia [Figure 7].
The monostotic form of fibrous dysplasia generally occurs during the second decade of life and becomes dormant by the third decade. The age of occurrence in our case was thus a comparatively rare incidence. The craniofacial form of fibrous dysplasia can be diffuse and may involve multiple bones. In fibrous dysplasia of the mandible, the mandibular canal may be displaced either inferiorly or superiorly. Petrikowski et al. suggested that upward displacement of the mandibular canal may be unique to fibrous dysplasia and could be pathognomonic, as in this case. Although the borders of fibrous dysplasia are known to be ill-defined,  they can appear well defined in panoramic and plain skull films (as in this case), if the border of the expansile portion of the lesion is superimposed over the mandible. Loss of lamina dura due to replacement of normal bone may be one of the diagnostic signs of fibrous dysplasia. In chronic cases, the lesion tends to become increasingly more radiopaque. Cystic lesions resembling aneurysmal bone cysts have been noted in association with the monostotic form. At least two radiographic images, exposed at right angles, are desirable to assess the extent of the lesion in all the dimensions. Because of the complexity of the anatomy, CT is helpful for assessing lesions in the maxilla. ,,
Differential diagnosis of the initial radiolucent stage must include the following: central ossifying fibroma (COF), osteomyelitis and early fibro-osseous lesions.  Because these lesions represent a variety of disease processes with different behaviors, including infection and endocrine dysfunction, prompt diagnosis incorporating clinical, radiographic and, occasionally, histologic findings is essential.
COF is a benign neoplasm that commonly has a radiographic and histologic appearance similar to that of fibrous dysplasia. In contrast to fibrous dysplasia, a well-defined capsule occasionally surrounds the lesion. Radiographically, a well-defined margin is consistent with COF, whereas the margins of fibrous dysplasia tend to merge with the surrounding normal bone. COF occurs mostly in the third and fourth decades of life, whereas fibrous dysplasia is most often discovered in the second decade. COF tends to occur more commonly in the anterior region of the mandible and is smaller in size, whereas fibrous dysplasia is more common in the posterior maxilla and the lesions tend to be larger. Both the lesions tend to expand the bone cortex.  Differentiation of these two lesions is critical because the treatment protocols are quite different. COF, although benign, must be enucleated for its potential to recur . Fibrous dysplasia is generally self-limiting and does not require treatment except for cosmetic reasons, pain, discomfort or impaired function.  If undertaken, the treatment consisting of recontouring or resection should be postponed until after cessation of skeletal growth, since early treatment may accelerate growth of the lesion.
Fibrous dysplasia may also mimic Paget's disease of bone on clinical examination, particularly if a patient with fibrous dysplasia does not present until later in life. In addition to the predilection of Paget's disease for an older population, certain radiographic and clinical features help to distinguish this lesion from other radiographically similar lesions. These features include thickening of the cortices, cotton wool appearance of the involved bone and increased blood levels of alkaline phosphatase.  The most useful clinical feature for distinguishing Paget's disease from fibrous dysplasia is that the former tends to occur bilaterally in the jaws, whereas the latter affects only one side.
Although there was no compelling indication to seek a biopsy in the case described here, any sudden change in the clinical presentation or behavior of the lesion might warrant further investigation, and thus an incisional biopsy was done. Treatment of fibrous dysplasia usually involves bony recontouring at the affected site to improve esthetics and function. The lesions can show surprising growth potential if they are surgically altered during their active growth phase.  Considering this aspect and the self-limiting nature of the lesion, no treatment was rendered in this case. However, recall of patient at regular intervals was advised.
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