Fibrous Dysplasia

Fibrous Dysplasia: Characteristics, Diagnosis, and Management

• Fibrous dysplasia is a developmental benign medullary fibro-osseous process characterized by the failure to form mature lamellar bone and arrest as woven bone that can be multifocal.
• It can affect any bone and occur in a monostotic form involving only one bone or a polyostotic form involving multiple bones.
• Fibrous dysplasia accounts for one of the 'F's in the popular mnemonic for lucent bone lesions FEGNOMASHIC.
• The monostotic form is far more common accounting for 70-80% of cases and is usually asymptomatic until the 2nd to 3rd decade but can be seen throughout adulthood, while the polyostotic form accounts for 20-30% and presents earlier, typically in childhood with about 60% showing symptoms before the age of 10 years.
• The diagnosis of fibrous dysplasia is mainly based on clinical and typical radiographic features, and if the imaging features are characteristic the lesion does not require histology.
• Histological confirmation is indicated in cases with atypical imaging appearance or in isolated monostotic lesions with clinical symptoms or other concerning features.
• The condition is often an incidental finding and is usually painless. Alternatively, it may present with bony expansion and remodeling or with pain.
• Management aims to establish the extent of the disease and the maintenance of bone quality via dietary measures and exercise. The prognosis is excellent and usually, no other treatment is required.
• However, monostotic fibrous dysplasia can lead to deformities leg-length differences and impingement or nerve compression syndromes. If a mass effect is severe, then surgery excision may be considered.
• Bone affected by fibrous dysplasia is weaker than normal and thus susceptible to pathological fractures.
• Sarcomatous dedifferentiation (most commonly osteosarcoma, fibrosarcoma, malignant fibrous histiocytoma, or rarely chondrosarcoma) is occasionally seen (< 1%) and is more common in the polyostotic form.
• Fibrous dysplasia was first described by the American bone pathologist Louis Lichtenstein in 1938 and the clinical, radiological and histological spectrum of findings has been later characterized by him and his colleague Henry Louis Jaffe in 1942.

Fibrous Dysplasia: Characteristics, Diagnosis, and Management

• Fibrous dysplasia is a developmental benign medullary fibro-osseous process characterized by the failure to form mature lamellar bone and arrest as woven bone that can be multifocal.
• It can affect any bone and occur in a monostotic form involving only one bone or a polyostotic form involving multiple bones.
• Fibrous dysplasia accounts for one of the 'F's in the popular mnemonic for lucent bone lesions FEGNOMASHIC.
• The monostotic form is far more common accounting for 70-80% of cases and is usually asymptomatic until the 2nd to 3rd decade but can be seen throughout adulthood, while the polyostotic form accounts for 20-30% and presents earlier, typically in childhood with about 60% showing symptoms before the age of 10 years.
• The diagnosis of fibrous dysplasia is mainly based on clinical and typical radiographic features, and if the imaging features are characteristic the lesion does not require histology.
• Histological confirmation is indicated in cases with atypical imaging appearance or in isolated monostotic lesions with clinical symptoms or other concerning features.
• The condition is often an incidental finding and is usually painless. Alternatively, it may present with bony expansion and remodeling or with pain.
• Management aims to establish the extent of the disease and the maintenance of bone quality via dietary measures and exercise. The prognosis is excellent and usually, no other treatment is required.
• However, monostotic fibrous dysplasia can lead to deformities leg-length differences and impingement or nerve compression syndromes. If a mass effect is severe, then surgery excision may be considered.
• Bone affected by fibrous dysplasia is weaker than normal and thus susceptible to pathological fractures.
• Sarcomatous dedifferentiation (most commonly osteosarcoma, fibrosarcoma, malignant fibrous histiocytoma, or rarely chondrosarcoma) is occasionally seen (< 1%) and is more common in the polyostotic form.
• Fibrous dysplasia was first described by the American bone pathologist Louis Lichtenstein in 1938 and the clinical, radiological and histological spectrum of findings has been later characterized by him and his colleague Henry Louis Jaffe in 1942.