Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis

Nikhil Diwan; Mahesh Chavan; Anagha Shete; Shivaji Khedkar

doi:10.4103/0975-8844.113710

CASE REPORT

Year : 2013 | Volume : 5 | Issue : 1 | Page : 67-70

Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis

Nikhil Diwan¹, Mahesh Chavan¹, Anagha Shete¹, Shivaji Khedkar²
¹ Department of Oral Medicine and Radiology, Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune, India
² Department of Oral Medicine and Radiology, YCMM and RDF Dental College and Hospital, Solapur, Maharashtra, India

Date of Web Publication

20-Jun-2013

Correspondence Address:
Nikhil Diwan
Department of Oral Medicine and Radiology, Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune - 411 018, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/0975-8844.113710

Abstract

Fibro-osseous lesions are benign mesenchymal tumors in which mineralized tissue, blood vessels, and giant cells, in varying proportions, replace normal bone. Although this group of lesions includes reactive lesions, harmatomas, and neoplasms, they cannot be distinguished only on the basis of the histopathology which can only confirm their common fibro-osseous nature. Definitive diagnosis requires thorough radiological evaluation. Computed tomographic images of craniofacial fibrous dysplasia on bone windows may be helpful and allow precise pre-operative diagnosis and surgical planning.

Keywords: Craniofacial fibrous dysplasia, computed tomographic images, radiographic diagnosis

How to cite this article:
Diwan N, Chavan M, Shete A, Khedkar S. Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis. J Orofac Sci 2013;5:67-70

How to cite this URL:
Diwan N, Chavan M, Shete A, Khedkar S. Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis. J Orofac Sci [serial online] 2013 [cited 2022 May 26];5:67-70. Available from: https://www.jofs.in/text.asp?2013/5/1/67/113710

Introduction

Fibro-osseous lesions are benign mesenchymal tumors in which mineralized tissue, blood vessels and giant cells, in varying proportions, replace normal bone. Normal bone and marrow are replaced by fibrous tissue and haphazardly distributed woven bone. ^[1] These are congenital, non-hereditary skeletal disorders. In most of the lesions, the deformity in the jaws begins as a progressively slow-growing pain less swelling. Growth of the lesion often slows or becomes arrested at the onset of puberty, maxilla being predominantly affected with the female predilection. ^[2] Craniofacial fibrous dysplasias (FD) comprise less than 1% of all primary bone lesions. ^[3] In this report, a rare case of FD with the extensive craniofacial involvement with the emphasis on computed tomographic (CT) features is presented. CT scan was extremely important to know the aggressive nature and thus, aid in its diagnosis as only jaw bone involvement was suspected on clinical examination.

Case Report

A 23-year-old Indian male reported with a complaint of gradually increasing painless swelling on the left side of the jaw for a year. The patient was born to parents with the consanguineous marriage. There was no history of similar complaint in other family members.

Extra oral examination revealed a diffuse swelling on the left side of the lower jaw extending from midline to the angle of the mouth region approximately 3 cm × 3 cm in size. The skin over the swelling appeared to be normal. On palpation, the swelling was hard, painless with the gradually merging borders. Serum calcium, phosphorous, and alkaline phosphatase levels were within the normal range.

Intraorally, a single, bony hard swelling in the labial vestibule (3 cm × 3 cm) was palpable. There was slight lingual expansion in the region of mandibular left canine. Distal tipping of mandibular left canine and lingual tipping of mandibular left first premolar was noticed.

A thorough radiographic evaluation was carried out. Complete skeletal survey ruled out lesions except in the skull and facial bones. An intraoral periapical radiograph of mandibular left canine-premolar region [Figure 1] revealed gross displacement of roots of canine and first premolar. A mixed lesion with indistinct borders was noted. The trabeculae in the periapical region were more dense, irregularly shaped and numerous giving a ground glass appearance and an area of opacification without any definite borders. Orthopantomograph [Figure 2] showed a diffuse mixed lesion extending from the mandibular left canine region up to the ascending ramus and the coronoid process and the condyle on the left side, with expansion and thinning of inferior cortex and posterior border of the ramus. The mandibular left third molar is displaced inferiorly below the roots of the second molar.

Figure 1: Intraoral periapical radiograph showing diffuse mixed lesion and ground glass appearance of trabeculae

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Figure 2: Orthopantomograph showing diffuse mixed lesion in left posterior mandible with thinning and expansion of inferior border of the mandible and inferior displacement of third molar

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The coronal CT image [Figure 3] revealed expansile lesion with patchy areas of ground glass appearance and hypodense areas scattered throughout the mandible and the skull base involving the left middle cranial fossa, with a diffuse involvement of the entire mandible, orbital plate of the frontal bone, sphenoid bone, and squamous temporal bone on the left side.

Figure 3: Coronal computed tomography showing hypodense, myxoid lesions in the mandible, skull base and the sphenoid bone

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The axial CT image [Figure 4] demonstrated diffuse involvement of multiple bones like the lateral wall of the orbit, lesser and greater wings of the sphenoid bone, the squamous portion of the temporal bone and the sphenoid sinus. Three dimensional CT image [Figure 5] demonstrated gross extensive, destructive pathologic lesion involving the mandible, the maxilla and squamous temporal bone.

Figure 4: Axial computed tomography shows myxematous, diffuse involvement of multiple bones

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Figure 5: 3dimensional computed tomography demonstrates gross extensive, destructive pathologic lesion involving the mandible, the maxilla, and squamous temporal bone

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Discussion

FD may be divided into three categories; monostotic (74%), polyostotic (13%) and craniofacial (13%). ^[4] Fibro-osseous lesions include reactive lesions, harmatomas, and neoplasms. Histopathology can only confirm their common fibro-osseous nature; the definitive diagnosis relies on the clinical and radiological finding. ^[5]

Kaban have classified lesions of FD as quiescent, non-aggressive, and aggressive on the basis of clinical behavior and radiographic findings. ^[6] The appearance of FD on plain radiographs depends on the activity of the tumor. In quiescent and non-aggressive lesions, the enlarged bone appears densely radiopaque or may have a "ground glass" appearance. Aggressive lesions demonstrate expansion of the bony contour along with cortical thinning or perforation. The teeth may get displaced and show root resorption. Lesions of the jaws are often poorly defined as compared to other long bones where they are circumscribed with a sclerotic periphery. ^[2] On the basis of radiological findings of bony destruction of mandibular cortex with displacement of mandibular third molar and extensive erosion of several craniofacial bones, the present case falls in to the aggressive category.

The radiological features of FD on conventional radiographs are classically a poorly defined fusiform enlargement (especially in the mandible) or generalized enlargement of the upper jaw and, if sufficiently large, with obliteration of the lumen of the maxillary antrum. ^[5]

CT remains the "gold-standard" imaging modality for FD. ^[7] As CT can be used to determine the extent, specific dimensions and radiodensity of FD with a high degree of precision and it would be valuable to be able to determine what are the long-term changes and which ones, if any, are associated with the continuous progression or reactivation. ^[8] Hence, the CT findings in craniofacial FD prove to be an important aid in the diagnosis.

Based on the CT appearance, Paget's disease, hyperparathyroidism, neurofibromatosis, and chondromyxoid fibroma can be considered as differential diagnosis for craniofacial FD.

Paget's disease is usually bilateral and seen in older patients. The degree of osseous thickening is not the same as in FD. ^[9] Hyperparathyroidism results in the formation of sclerotic bone with ground glass appearance, predominantly in secondary form of the disease. Skeletal manifestations are evident symmetrically along with the systemic hypercalcaemia. ^[10] Neurofibromatosis simulates FD particularly when neurofibroma erodes or originates in the skull bones. ^[11] In polyostotic FD, the skeletal lesions tend to be unilateral, more central, and more ossified having a ground glass appearance. ^[12] Chondromyxoid fibroma is an expansile mass in the skull base but less destructive than craniofacial FD. The CT findings of chondromyxoid fibroma are non-specific and almost always suggest a benign lesion. They typically have a lobulated outline with sharp margins, and the majority has a sclerotic rim ^[11] and approximately 13% of tumors show some discrete areas of calcification. ^[7] In cases where FD bears a cystic component or shows sudden expansion, aneurysmal bone cyst (ABC) is one of the differential condition to be noted. ^[13] There is a high incidence of accompanying tumors in 23-32% of ABCs. They may be caused by a reaction secondary to another bony lesion. Such lesions are called as secondary ABCs FD is one of the benign bony condition associated with ABCs. ^[14]

Advances in the knowledge of the molecular basis of FD hopefully will lead to effective non-surgical treatments based on gene therapy in the future and imaging modalities like CT will definitely contribute for better understanding of craniofacial FD.

Conclusion

Craniofacial FD is a rare entity. Radiological examination, especially, CT plays a significant role in the diagnosis of craniofacial FD. It helps us to identify the extent of the pathology, encroachment upon the vital structures, which will definitely aid in the treatment plan.

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