[Fibrous dysplasia]

Fibrous dysplasia is a tumorlike, benign lesion, caused by sporadic mutation during early embryogenesis. The skeletal involvement becomes increasingly visible during growth. The number and extent of dysplastic lesions increase until the age of 15. The polyostotic form is often associated with endocrine dysfunction, which should be diagnosed and treated early. Malignant transformation of fibrous dysplastic lesions is less than 1%; therefore, treatment or resection of the lesion itself is not necessary. The progress of the lesions during growth can lead to pain, fractures, and deformities. Bisphosphonates are effective for pain relief, but have no assured effect on the natural history of the disease. Fracture healing is not compromised by the disease. Conservative treatment with casts is therefore effective, especially for the upper limbs. The surgical approach with deformity correction and stabilization remains challenging particularly with regard to the proximal femur. Intramedullary devices should be preferred to plates, if possible.