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Fibrous Dysplasia

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Topic updated on 08/08/16 5:18pm
Introduction
  • A developmental abnormality caused by failure of the production of normal lamellar bone
    • areas of the skeleton remain poorly mineralized trabeculae
  • 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
    • location
      • any bone can be involved
      • the proximal femur is most common site, followed by rib, maxilla, and tibia
  • Genetics
    • GS alpha protein (chromosome 20q13) activating mutation (affects cAMP signaling pathway leading to increased production of cAMP)  
    • not inherited
    • 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
      • 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
  • Prognosis
    • 1% risk of malignant transformation to osteosarcoma, fibrosarcoma, or malignant fibrous histiocytoma
      • poor prognosis
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 than neurofibromatosis
        • may or may not be present with fibrous dysplasia
        • by definition present with McCune-Albright syndrome
      • swelling around lesion
Imaging
  • Radiographs
    • 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
    • vertebral collapse and 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 
Differentials & Groups
 
Multiple lesions in young patients (1)
 
Treatment is Observation alone (2)
 
Benefits from Bisphonate therapy
   
Fibrous dysplasia
 
 
   
Eosinophilic granuloma
 
 
 
   
Lymphoma
     
 
   
Leukemia
     
 
   
Enchondroma / Olliers / Marfucci's
 
 
 
   
Osteochondroma / MHE
 
 
 
   
NOF / Jaffe-Campanacci syndrome
 
 
 
   
Hemangioendothelioma
     
 
   
Paget's
 
 
 
   
Metastatic Disease        
   
Myeloma
 
 
 
 
   
ASSUMPTIONS: (1) Younger patient is < 40 yrs; (2) assuming aymptomatic and no impending fracture
 
IBank
 
Location
Age
Xray
Xray
CT
B. Scan
MRI
MRI
Histo(1)
Case A fibula
10 yrs.
   
   
Case A spine  
 
 
Case B radius  
 
     
Case C humerus  
 
 
   
Case D skull  
 
       
(1) - histology does not always correspond to clinical case


 

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Qbank (7 Questions)

TAG
(SBQ13.1) 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?
Topic Review Topic
FIGURES: A   B        

1. Neurofibromatosis
2. Holt-Oram Syndrome
3. McCune-Albright Syndrome
4. Fibular hemimelia
5. Ellis-van-Creveld Syndrome

PREFERRED RESPONSE ▶
TAG
(OBQ09.21) All of the following are characteristic of McCune-Albright syndrome EXCEPT? Topic Review Topic

1. Caused by a mutation in G(s)alpha subunit
2. Cafe-au-lait spots
3. Polyostotic fibrous dysplasia
4. Multiple neurofibromas
5. Precocious puberty

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

1. Fibrous dysplasia
2. Diastrophic dysplasia
3. Cleidocranial dysostosis
4. Osteogenesis imperfecta
5. Achondroplasia

PREFERRED RESPONSE ▶
TAG
(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? Topic Review Topic
FIGURES: A   B   C   D   E  

1. Figure A
2. Figure B
3. Figure C
4. Figure D
5. Figure E

PREFERRED RESPONSE ▶
TAG
(OBQ07.231) A 17-year-old high-school track athlete complains of vague pain along his anterior tibia. He denies any specific trauma to this area. Radiographs are seen in Figures A and B. A biopsy specimen in low and high power is seen in Figure C and D, respectively. What is the most likely diagnosis? Topic Review Topic
FIGURES: A   B   C   D    

1. Adamantinoma
2. Osteomyelitis
3. Fibrous dysplasia
4. Osteosarcoma
5. Stress fracture

PREFERRED RESPONSE ▶
TAG
(OBQ06.240) A genetic abnormality in the cyclic AMP signaling pathway is involved in which of the following conditions? Topic Review Topic

1. Achondroplasia
2. Hypochondroplasia
3. Multiple hereditary exostosis
4. Fibrous dysplasia
5. Neurofibromatosis type I

PREFERRED RESPONSE ▶



Cases

http://upload.orthobullets.com/cases/2622/021d669e-e390-4ba6-8fc6-b9ce25f00acb_shpcrk_hip..jpg http://upload.orthobullets.com/cases/2622/a6eb090a-51ae-40a0-9ee9-c13bff5beaa9_shpcrk_hip.jpg http://upload.orthobullets.com/cases/2622/2d10a29b-cc41-4ef5-b21f-1c3402912d7c_shep_crk..jpg
HPI - pain in the right hip since few days . no injury walking with a limp
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140 responses
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HPI - The patient presents with intermitten right dull hip pain for the last month.
poll
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680 responses
http://upload.orthobullets.com/cases/1615/anw fib dyspalsia.jpg http://upload.orthobullets.com/cases/1615/anw lat.jpg
HPI - pain rt hip since 3 months.with pain on walking
poll What is your treatment for this lesion
9/5/2013
261 responses
http://upload.orthobullets.com/cases/1318/fib dys.jpg http://upload.orthobullets.com/cases/1318/fib dysplasia hasib.jpg http://upload.orthobullets.com/cases/1318/hasib fib dyspalsia.jpg
HPI - pain in the rt hip thigh since 6 mths pain increases on long walking.
poll prophlactic nailing or prophlactic nailing with curettage of lesion
11/10/2012
30 responses
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Videos

video
Histologic review of fibrous dysplasia by Dr. John Minarcik.
11/9/2014
172 views
3
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