Fibrous dysplasia in children and its management

Abstract

Purpose of review: The purpose of this review is to provide a comprehensive overview into the diagnosis and management of fibrous dysplasia (FD) in children.

Recent findings: FD is a mosaic disorder arising from somatic Gα s variants, leading to impaired osteogenic cell differentiation. Fibro-osseous lesions expand during childhood and reach final disease burden in early adulthood. The mainstay of treatment focuses on surgical correction of skeletal deformities, physiatric care, and medical management of associated hyperfunctioning endocrinopathies. Bisphosphonates may be helpful to treat bone pain, but do not alter lesion quality or progression. Emerging evidence suggests that the RANKL inhibitor denosumab may be effective in improving lesion activity and mineralization, however further studies are needed to determine the potential utility of this and other novel therapies, particularly in children with FD.

Summary: Management of children with FD has unique challenges related to skeletal growth and age-related lesion progression. Inclusion of children in clinical research is critical to develop effective treatment strategies to treat FD lesions and prevent their development.

FIGURE 1.

Representative histologic images of fibrous dysplasia (FD) (H&E stain A, B, C & Von Kossa stain D). (a) Typical appearance of FD with thin, discontinuous, curvilinear trabeculae (b) enveloped by fibrous tissue (ft) and fibroblastic spindle cells (sc). (b) Sharpey’s fibers bridge between bone and fibrous tissue (circled) due to collagen bundles oriented perpendicular to the bone surface. (c) Abundant osteoclasts on the surface of bone trabeculae (arrows). (d) Under mineralization of dysplastic bone (MB) with excess osteoid formation (os) and fibrous tissue (ft).

FIGURE 2.

Radiographic features of FD. (a) Bilateral femoral involvement with a right-sided bowing deformity (arrow). Note the expansile ground glass homogeneity, with cortical thinning throughout. The left femur has undergone surgical stabilization with plate and screw placement. (b) FD involving the ulna shows an expansile, radiolucent lesion (arrow). (c) FD involving the entire humerus demonstrates diffuse radioluceny, expansion, and cortical thinning. Note the presence of a small insufficiency fracture (arrow).

FIGURE 3.

Representative clinical images. (a) Photograph of a patient with moderate scoliosis, leading to pelvic obliquity. Note the characteristic skin hyperpigmentation located along the midline of the neck and back with jagged borders. (b) Representative image of ¹⁸F-sodium positron-emission tomography-computed tomography (PET-CT) scan in a patient with polyostotic FD. Increased tracer uptake is evident in FD lesions involving the skull, ribs, spine, pelvis, and lower extremities (arrows). (c) A patient with expansion of FD in the maxillary region has resulting left-sided facial asymmetry and vertical orbital dystopia. Note the presence of characteristic skin hyperpigmentation along the neck and shoulder area. (d) Computed tomography scan shows expansile lesions involving the frontal, sphenoid, and occipital bones (asterisks). Note the characteristic expansion and ground glass heterogeneity. A small lesion is located in the body of the cervical vertebra (arrow), demonstrating a more radiolucent appearance.