Fibrous Dysplasia

Fibrous Dysplasia
Etiology • Unknown • A dysplastic process or developmental lesion of bone
Clinical Presentation • An asymptomatic tumor-like mass or deformity of bones • May be monostotic (80%) or polyostotic (20%) • Uncommonly, the polyostotic form may occur with endocrine
hyperfunction and focal cutaneous pigmentation (McCuneAlbright syndrome).
• Slow-growing, painless swelling of affected bone(s) • Mandibular body most common site • Facial asymmetry a frequent presenting sign • Tooth displacement and malocclusion common • Maxillary jaw lesions may be accompanied by involvement of
the zygoma, sphenoid, and, less commonly, the occiput (the craniofacial variant).

Radiographic Findings • Ill-defined, uniformly radiopaque enlargement with “ground-
glass” qualities and diffuse, blended margins • Mandibular lesions may show loculation. • The craniofacial form may show skull base thickening. • Intraoral films may show lamina dura obscurity.
Diagnosis • Clinical appearance • Radiographic qualities • Biopsy showing typical irregular trabeculae of woven bone
(“Chinese characters”) and fibroblastic, vascularized stroma
Differential Diagnosis • Chronic sclerosing osteomyelitis • Localized Paget’s disease • Osteosarcoma • Cemento-osseous dysplasias
Treatment • Cosmetic recontouring, if necessary • Observation only, if lesions are minimally developed and stable
Prognosis • Most stabilize in adult life • Some relapse noted in up to one-half of surgically recontoured
cases • Malignant transformation rare unless previously irradiated