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Dr/ Hytham Nafady
replacement of the normal lamellar cancellous bone by abnormal fibrous tissue.
Types of fibrous dysplasia
Age: 3-30. Sex: F > M.
Polystotic FDis more aggressive than monostotic FD.
The lesions usually progress in number till the end of skeletal maturation, by then they become quiescent
in only about 5% of cases it continue to enlarge after that.
Complications of fibrous dysplasia
1. Pathological fracture.2. Bone deformity.3. Massive cartilage hyperplasia.4. Accelerated bone growth.5. Sarcomatous degeneration.
Shepherd crock deformity
is very rear, it may occur spontaneously or following radiation therapy.
Radiological Criteria: Cortical destruction. Extraosseous soft tissue
Location : Long bones specially the neck of femur Skull (including calvarium, skull base, facial
bones & mandible), Pelvis Ribs (fibrous dysplasia is the most common
cause of rib expansion).Distribution: Unilateral or rarely bilateral asymmetrical.
Long bone fibrous dysplasia
Meta-diaphyseal. The epiphysis is usually spared. Central May be expansile. Cortex thinned or scalloped with no cortical break through or
periosteal reaction (smooth outer cortex).Density: depend upon the ratio between the fibrous & osseous
tissues, Sclerotic (increased osseous content), or Lytic (increased fibrous content) or Ground glass, (relatively equal ratios between fibrous & osseous
content).Margin: Well defined sclerotic margin (Geographic bone
destruction). The sclerotic margin may be thick (rind sign).
Pelvis fibrous dysplasia
Expansile, lytic, bubbly lesion. The degree of expansion & the bubbly nature
are quite marked in the pelvis rather than long bones.
Rib fibrous dysplasia
Expansile lytic lesion with no rib destruction.
Calvarium Skull base Facial bones
Widening of the diploic space.Displacement of the outer table.Sparing of the inner table.
Narrowing of the neural foramina.
Density: •Sclerotic or Ground glass, •Common
•Lytic or mixed •Rare
DDx: Paget disease Skull base tumors Ossifying fibroma
(the inner table is involved). Fibrous dysplasia conforms to the shape of the involved bone.
Special forms of fibrous dysplasia
Leontiasis ossea. Cherubism. Mc Cune Albright syndrome.
A special form of polystotic fibrous dysplasia that affects the skull & facial bones.
Familial fibrous dysplasia of the jaws.
Mc Cune Albrightsyndrome
Almost exclusively affect females.
Mc Cune Albright syndrome Neurofibromatosis
Never cross the midline and Cross the midline.
(coast of Maine)
(coast of California)