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Review
. 2017 Sep;23(6):697-708.
doi: 10.1111/odi.12563. Epub 2016 Sep 1.

Fibrous dysplasia of bone: craniofacial and dental implications

A B Burke  1 , M T Collins  1 , A M Boyce  1   2   3
Affiliations
Review

Fibrous dysplasia of bone: craniofacial and dental implications

A B Burke et al. Oral Dis. 2017 Sep.

Abstract

Fibrous dysplasia (FD) is a rare bone disease caused by postzygotic somatic activating mutations in the GNAS gene, which lead to constitutive activation of adenylyl cyclase and elevated levels of cyclic AMP, which act on downstream signaling pathways and cause normal bone to be replaced with fibrous tissue and abnormal (woven) bone. The bone disease may occur in one bone (monostotic), multiple bones (polyostotic), or in combination with hyperfunctioning endocrinopathies and hyperpigmented skin lesions (in the setting of McCune-Albright Syndrome). FD is common in the craniofacial skeleton, causing significant dysmorphic features, bone pain, and dental anomalies. This review summarizes the pathophysiology, clinical findings, and treatment of FD, with an emphasis on the craniofacial and oral manifestations of the disease.

Keywords: GNAS gene; McCune-Albright syndrome; craniofacial bone disease; dental anomalies; fibrous dysplasia.

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Figures

Figure 1
Figure 1. Signaling pathway
Fibrous dysplasia (FD) results from post-zygotic, activating mutations in the gene GNAS, which encodes for the Gsα subunit of the G protein complex. In FD, a mutated Gsα results in ligand-independent, continuous activation of adenylyl cyclase, resulting in excess production of intracellular cAMP. In bone, this causes proliferation of bone marrow stromal cells, leading to fibrosis, loss of hematopoiesis/marrow adipocytes, and a structurally abnormal matrix.
Figure 2
Figure 2. Axial and appendicular skeletal findings
(A) Typical Technetium-99m (99mTc)bone scan, showing uptake in areas of fibrous dysplasia (FD) – including the skull, bilateral arms, legs and pelvis. (B) Expansion and bowing of the lower extremities in a patient with polyostotic disease. Rods have been placed to help stabilize the right femur and tibia. “Shepherd's crook” deformity can be visualized at the left femoral neck angle (asterisk). (C) Photograph of a patient with lower extremity deformity and leg-length discrepancy caused by FD. (D) AP Chest radiograph with severe scoliosis caused by FD of the vertebral column.
Figure 3
Figure 3. Craniofacial monostotic fibrous dysplasia
Patient with craniofacial monostotic fibrous dysplasia of the right maxilla. (A & B) Pre-operative photograph and axial computed tomography (CT) scan showing expansion of the right maxilla. The CT is remarkable for characteristic ground-glass appearance of lesion, extending from the alveolar bone (red arrow). (C & D) Post-operative photograph and axial CT scan after recontouring and debulking of the right maxillary lesion. Note the improved facial symmetry and contour of the right maxillary alveolus.
Figure 4
Figure 4
Craniofacial polyostotic fibrous dysplasia. Imaging from two individuals with polyostotic craniofacial fibrous dysplasia (FD) in the setting of McCune-Albright Syndrome. (A) 3D CT of a 17 year-old male, showing extensive disease of the midface and orbital asymmetry. (B) Axial CT scan showing typical ground-glass appearance of the left midface and skull base, obliterating the region of the sphenoid sinuses (asterisk). (C) Axial CT from a 33 year-old female showing the narrowing of the bilateral optic canals (outlined in red).
Figure 5
Figure 5. Extraskeletal findings
(A) Characteristic café-au-lait macule seen in McCune-Albright Syndrome. The borders are commonly referred to as resembling the “coast of Maine,” and the lesion typically respects the midline, following the lines of cellular migration (lines of Blaschko). (B) Thyroid ultrasound (transverse view) showing multilocular hypoechoic lesions (arrowheads), common in McCune-Albright Syndrome
Figure 6
Figure 6. Histology craniofacial fibrous dysplasia
(A) H&E stain at 4× and (B) 20× of craniofacial fibrous dysplasia lesion. The boney matrix has been replaced by proliferating soft tissue. Osteoclasts are present in the lower panel of (B), arrowheads. (C) Masson trichrome stain from the same lesion at 4× and (D) 20×. (Dark blue = bone; Red = osteoid/woven bone; Light blue = fibrous tissue)
Figure 7
Figure 7. Fibrous dysplasia of the jaws
(A) Significant malocclusion in a patient with craniofacial FD. This patient has a right unilateral crossbite, dental crowding and rotation of teeth. (B) Panoramic radiograph of the same patient showing the right maxilla and mandible (arrows) affected by fibrous dysplasia. The right mandibular condyle is also affected (asterisk). The left side is unaffected by the disease.
Figure 8
Figure 8. Dental anomalies in fibrous dysplasia
Dental anomalies can be seen when fibrous dysplasia (FD) affects the jaws. (A) Taurodontism and fused pulp chambers (asterisk) seen in the molars of a FD patient. (B) Hypomineralization of primary dentition (arrow heads). (C) Mandibular FD lesion causing splaying and dilaceration of the molar roots, and blunting of the distal root of the first molar (arrow). The inferior alveolar nerve is also displaced inferiorly (green outline).
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References

    1. Akil O, Hall-Glenn F, Chang J, Li A, Chang W, Lustig LR, Alliston T, Hsiao EC. Disrupted bone remodeling leads to cochlear overgrowth and hearing loss in a mouse model of fibrous dysplasia. PLoS One. 2014;9:e94989. - PMC - PubMed
    1. Akintoye SO, Boyce AM, Collins MT. Dental perspectives in fibrous dysplasia and McCune-Albright syndrome. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013;116:e149–55. - PMC - PubMed
    1. Akintoye SO, Kelly MH, Brillante B, Cherman N, Turner S, Butman JA, Robey PG, Collins MT. Pegvisomant for the treatment of gsp-mediated growth hormone excess in patients with McCune-Albright syndrome. J Clin Endocrinol Metab. 2006;91:2960–6. - PubMed
    1. Akintoye SO, Lee JS, Feimster T, Booher S, Brahim J, Kingman A, Riminucci M, Robey PG, Collins MT. Dental characteristics of fibrous dysplasia and McCune-Albright syndrome. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003;96:275–82. - PubMed
    1. Amit M, Collins MT, Fitzgibbon EJ, Butman JA, Fliss DM, Gil Z. Surgery versus watchful waiting in patients with craniofacial fibrous dysplasia--a meta-analysis. PLoS One. 2011;6:e25179. - PMC - PubMed

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