Fibrous Dysplasia

Fibrous Dysplasia (FD) represents a benign, nonhereditary skeletal condition arising from post-zygotic GNAS gene mutations, leading to abnormal bone remodeling. Normal bone and marrow get progressively substituted by fibro-osseous tissue, resulting in structurally weak, expanded bones prone to complications. It manifests in monostotic (single bone, ~70% cases) or polyostotic forms, often diagnosed between ages 10-30 via imaging showing "ground glass" appearance.?

Types and Prevalence

Monostotic FD typically affects long bones like femur or tibia, remaining localized and less severe. Polyostotic variants involve multiple sites, sometimes associating with McCune-Albright syndrome featuring endocrine issues and café-au-lait spots. Incidence estimates range from 1 in 5,000-10,000, with craniofacial involvement risking nerve compression.?

Symptoms and Complications

Patients experience bone pain, pathologic fractures, deformities, scoliosis, or cranial deficits like vision/hearing loss. Facial asymmetry and mobility limitations arise in skull-affected cases. Severity varies from asymptomatic incidental findings to debilitating multisystem involvement.?

Diagnosis and Management

Radiographs reveal radiolucent lesions with irregular trabeculae; biopsy confirms fibrous stroma and woven bone. Treatments include bisphosphonates for pain, surgical contouring or fixation for deformities, and monitoring to prevent fractures. Malignancy risk stays under 1%, emphasizing supportive care