Updated: 6/22/2021

Fibrous Dysplasia

0%
Topic
Review Topic
0
0
0%
0%
Flashcards
5
N/A
N/A
Questions
18
0
0
0%
0%
Evidence
15
0
0
0%
0%
Videos / Pods
1
0%
0%
Cases
4
Topic
Images
https://upload.orthobullets.com/topic/8038/images/4 - Fig 15 abcd_moved.jpg
https://upload.orthobullets.com/topic/8038/images/021a_moved.jpg
https://upload.orthobullets.com/topic/8038/images/prfm1[1]_moved.jpg
https://upload.orthobullets.com/topic/8038/images/cafeaulait[1]_moved.jpg
  • summary
    • Fibrous Dysplasia is a developmental abnormality caused by a GS alpha protein mutation that leads to failure of the production of normal lamellar bone.
    • The condition usually presents in patients who are less than 30 years of age with an asymptomatic lesion that is found incidentally on radiographs.
    • Diagnosis is made with radiographs showing a lesion with ground glass appearance or a "punched-out" lesion with a well-defined margin of sclerotic bone.
    • Treatment is usually nonoperative with bisphosphonates for pain control. Surgical management is indicated for lesions that lead to bone deformities such as scoliosis or coxa vara.
  • Epidemiology
    • Demographics
      • male:female ratio
        • females > males
      • age bracket
        • found in any and all ages
        • onset for 75% of patients at <30 years of age
    • Anatomic location
      • any bone can be involved
      • the proximal femur is most common site, followed by rib, maxilla, and tibia
  • Etiology
    • Genetics
      • associated with GNAS mutation
        • GS alpha protein (chromosome 20q13) activating mutation (affects cAMP signaling pathway leading to increased production of cAMP)
      • high production of FGF-23 which may lead to hypophosphatemia
    • Associated conditions
      • orthopedic manifestations
        • McCune Albright syndrome
          • condition defined by the presence of
            • skin abnormalities (cafe au lait spots in coast of Maine pattern)
            • endocrine abnormalities (precocious puberty)
              • renal phosphate wasting due to FGF-23 (oncogenic osteomalacia)
            • unilateral polyostotic fibrous dysplasia
              • obtain AP spine radiographs to look for scoliosis
        • Mazabraud syndrome
          • polyostotic fibrous dysplasia
          • soft-tissue intramuscular myxomas
        • Osteofibrous dysplasia
          • rare form that primarily affects the tibia and is confined to the cortices
      • nonorthopedic manifestations
        • severe cranial deformities with blindness
  • Presentation
    • Symptoms
      • usually asymptomatic and discovered as an incidental finding
      • may have swelling or deformity
      • bone lesions may be monostotic (80%) or polystotic (20%)
      • pain from stress fractures
    • Physical exam
      • inspection
        • cafe au lait spots
          • larger and more irregular borders ("coast of Maine") than neurofibromatosis
          • may or may not be present with fibrous dysplasia
          • by definition present with McCune-Albright syndrome
        • swelling around lesion
        • scoliosis
  • Imaging
    • Radiographs
      • hip/pelvis radiograph
        • central lytic lesions in medullary canal (diaphysis or metaphysis)
        • may have cortical thinning with expansile lesion
        • highly lytic lesions or a ground glass appearance
        • "punched-out" lesion with well-defined margin of sclerotic bone is common
        • modest expansion of bone
        • Shepherd's crook deformity
      • AP spine radiograph
        • vertebral collapse
        • kyphoscoliosis
    • Bone scan
      • usually warm
  • Studies
    • Gross - yellow-white gritty tissue
    • Histology
      • characteristic look of "alphabet soup" or "chinese letters"
      • fibroblast proliferation surrounding islands of woven bone
        • woven bone lacks osteoblastic rimming (osteofibrous dysplasia has osteoblastic rimming)
      • trabeculae of osteoid and bone in fibrous stroma with metaplastic cartilage or areas of cyst degeneration
      • mitotic figures are common
  • Treatment
    • Nonoperative
      • observation
        • indications
          • asymptomatic patients
      • bisphosphonate therapy
        • indications
          • symptomatic polyostotic fibrous dysplasia
        • effective in decreasing pain and reducing bone turnover
    • Operative
      • internal fixation and bone grafting
        • indications
          • symptomatic lesions
          • impending/actual fractures through lesions in areas of high stress (femoral neck)
          • severe deformity
          • neurologic compromise in the spine
        • technique
          • never use autogenous cancellous bone, as the transplanted bone will quickly turn into fibrous dysplastic woven bone
          • use cortical or cancellous allografts
          • intramedullary device more effective than a plate in the lower extremity
      • osteotomies
        • indications
          • coxa vara deformity
            • intertrochanteric osteotomy
  • Differential
    • Fibrous Dysplasia Differential 
      Multiple lesions in young patients
      Treatment is Observation alone
      Benefits from Bisphonate therapy
      Fibrous Dysplasia 
      Eosinophilic granuloma
      Lymphoma
      Leukemia

      Enchondroma / Olliers / Maffucci's
      Osteochondroma / MHE
      NOF /Jaffe-Campanacci syndrome
      Hemangioendothelioma
      Paget's
      Metastatic Disease
      Myeloma
  • Prognosis
    • 1% risk of malignant transformation to osteosarcoma, fibrosarcoma, or malignant fibrous histiocytoma
      • poor prognosis

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Flashcards (5)
Cards
1 of 5
Questions (18)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(SBQ13PE.1) A 6-year-old being evaluated in your clinic presents with the clinical findings and radiographs shown in Figures A and B. What is the most likely diagnosis?

QID: 4911
FIGURES:
1

Neurofibromatosis

15%

(808/5556)

2

Holt-Oram Syndrome

2%

(98/5556)

3

McCune-Albright Syndrome

82%

(4554/5556)

4

Fibular hemimelia

0%

(6/5556)

5

Ellis-van-Creveld Syndrome

1%

(51/5556)

L 2 B

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ09.74) A mutation in a G(s) alpha protein (activating G protein that increases cAMP) results in which of the following diseases?

QID: 2887
1

Fibrous dysplasia

82%

(1835/2245)

2

Diastrophic dysplasia

6%

(125/2245)

3

Cleidocranial dysostosis

3%

(65/2245)

4

Osteogenesis imperfecta

5%

(112/2245)

5

Achondroplasia

5%

(102/2245)

L 1 B

Select Answer to see Preferred Response

(OBQ09.21) All of the following are characteristic of McCune-Albright syndrome EXCEPT?

QID: 2834
1

Caused by a mutation in G(s)alpha subunit

10%

(269/2721)

2

Cafe-au-lait spots

4%

(119/2721)

3

Polyostotic fibrous dysplasia

5%

(125/2721)

4

Multiple neurofibromas

76%

(2078/2721)

5

Precocious puberty

4%

(119/2721)

L 2 B

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ07.231) A 17-year-old high-school track athlete complains of vague pain along his knee. He denies any specific trauma to this area. A radiograph is seen in Figure A. A biopsy specimen in low and high power is seen in Figure C and D, respectively. What is the most likely diagnosis?

QID: 892
FIGURES:
1

Adamantinoma

21%

(551/2588)

2

Osteomyelitis

1%

(16/2588)

3

Fibrous dysplasia

66%

(1708/2588)

4

Osteosarcoma

7%

(191/2588)

5

Stress fracture

4%

(110/2588)

L 3 C

Select Answer to see Preferred Response

(OBQ07.26) The G-protein coupled family of receptors play a crucial role in transmembrane cytokine signaling. Point mutation in the Gs-alpha subunit of this receptor is responsible for a specific bone/soft tissue disease. Which of the following radiographs corresponds to this disease?

QID: 687
FIGURES:
1

Figure A

17%

(345/2070)

2

Figure B

3%

(70/2070)

3

Figure C

6%

(126/2070)

4

Figure D

10%

(200/2070)

5

Figure E

63%

(1310/2070)

L 2 C

Select Answer to see Preferred Response

(OBQ06.240) A genetic abnormality in the cyclic AMP signaling pathway is involved in which of the following conditions?

QID: 251
1

Achondroplasia

10%

(164/1662)

2

Hypochondroplasia

4%

(59/1662)

3

Multiple hereditary exostosis

12%

(206/1662)

4

Fibrous dysplasia

66%

(1092/1662)

5

Neurofibromatosis type I

8%

(137/1662)

L 2 B

Select Answer to see Preferred Response

Evidence (15)
VIDEOS & PODCASTS (2)
CASES (4)
EXPERT COMMENTS (14)
Private Note