FIBROUS DYSPLASIA Fibrous Dysplasia University of Pretoria DEFINITION

FIBROUS DYSPLASIA Fibrous Dysplasia University of Pretoria

DEFINITION Uncommon, benign disorder characterized by a tumor-like proliferation of fibro-osseous tissue Fibrous Dysplasia University of Pretoria

AETIOLOGY • Cause unknown Tissue in the tumour is immature, woven bone that cannot differentiate in to mature, lamellar bone Fibrous Dysplasia University of Pretoria

INCIDENCE • • • Relatively common Usually monostotic Mainly children & adolescents Median age of onset = 8 yrs MALE > FEMALE Fibrous Dysplasia University of Pretoria

CLINICALLY ( Mc. Cune-Albrights ) • • • Polyostotic disease (Usually unilateral) Skin pigmentation (Café au lait) Precocious puberty (endocrinopathy) Presents earlier Malignant transformation 4% (chondrosarcoma or osteosarcoma) Fibrous Dysplasia University of Pretoria

SITES • • • Ribs commonest 40% Lower limbs > upper limbs Craniofacial --> skull deformity Epiphyses usually spared Polyostotic -> pain , fracture , deformity Fibrous Dysplasia University of Pretoria

RADIOLOGY • • • Lucent lesion in medullary space Sclerotic margin Ground glass appearance typical No periosteal reaction Shepherds crook deformity Expansion of cortex Fibrous Dysplasia University of Pretoria

RADIOLOGY Fibrous Dysplasia University of Pretoria

PATHOLOGY • Bone displaced by firm , gritty whitish tissue • Vascular tumour , poorly orientated bone trabeculae • Bone is woven rather than lamellar • Lack of osteoblastic rimming Fibrous Dysplasia University of Pretoria

DIFFERENTIAL DIAGNOSIS • • • Pagets disease FCD Hyper parathyroidism Osteoblastoma Osteosarcoma Fibrous Dysplasia University of Pretoria

TREATMENT • Monostotic -> curettage and grafting if symptomatic • Polyostotic -> symptomatic treatment • May require osteotomy for deformity or lengthening Fibrous Dysplasia University of Pretoria

PROGNOSIS • Monostotic lesions cease activity at puberty • May be activated by pregnancy • Polyostotic 85% -> pathological # • Malignant change occurs after radiotherapy Fibrous Dysplasia University of Pretoria