Fibrous Dysplasia

Question 1

What bone disorder is thought to be caused by a Gs alpha protein mutation the affects the cAMP pathway?

Answer 1

fibrous dysplasia

Question 2

What is the risk of malignant transformation in fibrous dysplasia?

Answer 2

1%

Question 3

What are some disorders that involve fibrous dysplasia?

Answer 3

1) McCune-Albright (polyostotic fibrous dysplasia, cafe-au-lait spots, endocrine abnormalities)
2) Mazabraud syndrome (polyostotic fibrous dysplasia, soft tissue myxomas)

Question 4

What are the imaging and histological characteristics of fibrous dysplasia?

Answer 4

“ground glass” or “punched-out” lesions with sclerotic border on radiographs; may have Shepard’s crook deformity or spinal collapse leading to kyphoscoliosis; histology shows “chinese character” or “alphabet soup” of fibroblast surrounded by woven bone

Question 5

What is the treatment for fibrous dysplasia?

Answer 5

Observation, bisphosphonate therapy can slow growth and reduce pain
If impending/present fracture, ORIF with allograft (autogenous cancellous graft will turn over into fibrous lesion)