FIBROUS DYSPLASIA

Fibrous Dysplasia University of Pretoria

DEFINITION

Fibrous Dysplasia University of Pretoria

Uncommon, benign disorder characterized by a tumor-like proliferation of fibro-osseous tissue

AETIOLOGY

• Cause unknown

Fibrous Dysplasia University of Pretoria

Tissue in the tumour is immature, woven bone that cannot differentiate in to mature, lamellar bone

INCIDENCE

• Relatively common• Usually monostotic• Mainly children & adolescents• Median age of onset = 8 yrs• MALE > FEMALE

Fibrous Dysplasia University of Pretoria

CLINICALLY( McCune-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