Which of the following is NOT a TRUE statement about fibrous dysplasia?
The polyostotic form typically manifests in children < 10 years of age and may progress with age. Good to know: Fibrous dysplasia: It is characterized by the replacement of normal lamellar cancellous bone by an abnormal fibrous tissue that contain small, abnormally arranged trabeculae of immature woven bone. It may affect one bone (monostotic form) or several bones (polyostotic form) The monostotic form is the most common and is usually diagnosed in patients between 20 and 30 years of age without associated skin lesions. The polyostotic form typically manifests in children Monostotic fibrous dysplasia most commonly affects the femur paicularly the femoral neck as well as the tibia and ribs. Polyostotic fibrous dysplasia most commonly affects the maxilla and other craniofacial bones, ribs, and metaphyseal or diaphyseal poions of the femur or tibia. Radiological findings: In the long bones, the fibrous dysplasia lesions are typically well-defined, radiolucent areas with thin coices and a ground glass appearance. The aicular ends are usually spared. Involvement of the facial bones usually presents as radiodense lesions, which may create a leonine appearance ( leontiasis sea). Treatment: There is no established effective treatment. IV bisphosphonates therapy- improvement in bone pain and paial or complete resolution of radiographic lesions have been repoed after IV bisphosphonate therapy. Surgical stabilization is used to prevent pathologic fracture or destruction of a joint space to relieve nerve root or cranial nerve compression or sinus obstruction. Complication: Most common complication is pathological fracture Shepherd's crook deformity- if fracture occur at the femoral neck, it commonly lead to a deformity called "shepherd crook". Expanding bone lesions may cause pain, deformity and nerve entrapment. Sarcomatous transformation of either form of fibrous dysplasia is extremely rare, but it may occur spontaneously or, more commonly, after radiation therapy. Ref: Harrison 17/e page 2414 ; Ohopedic Imaging : A Practical Approach By Adam Greenspan 4/e, chapter 19.
Characterised by replacement of normal lamellar bone by an abnormal fibrous tissue
The polyostotic form is common in adults
Thin coices
Ground-glass appearance