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Updated: Mar 23 2025

Non-Ossifying Fibroma

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  • summary
    • Non-Ossifying Fibromas are benign fibrogenic lesions that result from dysfunctional ossification that are most commonly found in the metaphysis of long bones. Patients typically present between the ages of 5 and 15 with an asymptomatic lesion discovered incidentally on radiographs.
    • Diagnosis is made on radiographs with a characteristic metaphyseal eccentric "bubbly" lytic lesion surrounded by a sclerotic rim.
    • Treatment is observation as most lesions resolve spontaneously.
  • Epidemiology
    • Incidence
      • occurs in 30-40% of skeletally immature children
    • Demographics
      • more common in males (2:1)
      • common in children 5-15 years old
    • Anatomic location
      • metaphysis of long bones
      • 80% in lower extremity
        • distal femur > proximal tibia > distal tibia
        • uncommon in proximal femur, proximal humerus
  • Etiology
    • Mechanism
      • non-ossifying fibroma (NOF) is a benign fibrogenic lesion that is related to dysfunctional ossification
        • one of the most common benign bone tumors in childhood (with osteochondroma)
        • other names
          • metaphyseal fibrous defect
          • nonosteogenic fibroma
          • cortical desmoid
          • fibrous cortical defect
          • fibromatosis
          • fibroxanthoma
    • Pathophysiology
      • possibly due to abnormal osteoclastic resorption at the subperiosteal level during remodeling of the metaphysis
    • Associated conditions
      • Jaffe-Campanacci syndrome
        • congenital syndrome of multiple non-ossifying fibromas and
          • cafe au lait pigmentation
          • mental retardation
          • heart, eyes, gonads involved
      • neurofibromatosis
      • familial multifocal NOF
      • ABC
  • Presentation
    • Symptoms
      • asymptomatic
        • usually found incidentally
      • may present with pathologic fracture
  • Imaging
    • Radiographs
      • diagnostic
      • metaphyseal eccentric "bubbly" lytic lesion surrounded by sclerotic rim
        • cortex may be expanded and thin
        • length > width
      • as bone grows
        • migrates to diaphysis
        • lesions enlarge (1-7cm)
      • as patient approaches skeletal maturity, lesions become sclerotic
      • avulsion of adductor magnus insertion in the posteromedial aspect of the distal femur may produce a similar looking lesion
    • CT
      • quantitative CT shown to be useful in predicting fracture risk
  • Studies
    • Histology
      • classic characteristics are
        • fibroblastic spindle cells in whirled or storiform pattern (helicopter in wheat field)
        • fibroblastic connective tissue background
        • numerous lipophages and giant cells
        • hemosiderin pigmentation
        • occasional ABC component
  • Differential
    • Giant cell tumor
      • painful
      • rare in skeletally immature
      • no mineralization
    • Osteosarcoma
      • painful
      • irregular zone of bony destruction with less defined zone of transition
      • periosteal reaction
      • mineralized soft tissue mass
      • Differential of non-Ossifying Fibroma
      • "Bubbly" lytic lesion on xray
      • Hemosiderin seen on Histology
      • Treatment is Observation alone
      • NOF
      • o
      • o
      • o
      • ABC
      • o
      • UBC
      • o
      • PVNS
      • o
      • Fibrous dysplasia
      • o
      • Enchondroma
      • o
      • Osteochondroma
      • o
      • Eosinophillic granuloma
      • o
      • Paget's
      • o
  • Treatment
  • Complications
    • Pathologic fracture
      • incidence
        • 90% occur in the lower extremity
          • 50% occur in the distal tibia
      • risk factors
        • >50% involvement of transverse diameter
        • >33mm length in weight-bearing bones (femur and tibia)
      • treatment
        • cast immobilization
          • indications
            • nondisplaced fractures
  • Prognosis
    • Usually spontaneously resolves
    • No malignant or metastatic potential
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QID 219481 (Type "219481" in App Search)
An 11-year-old is brought in to the urgent care with pain and swelling over his shin after being kicked by one of his classmates in his special education class. His presenting radiograph is shown in Figure A. He is able to bear weight on the extremity and has no deficits on exam, but he is noted to have numerous broad-based, brown macules on the extremities, wears glasses, and is being followed for an expansile lesion in his mandible. Which of the following conditions does the patient most likely have?
  • A

Jaffe-Campanacci syndrome

36%

269/748

Jaffe-Lichenstein syndrome

3%

23/748

Maffucci syndrome

10%

72/748

Mazabraud syndrome

3%

20/748

McCune Albright syndrome

48%

358/748

  • A

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Pathology⎪Non-ossifying Fibroma
  • Pathology
  • - Non-Ossifying Fibroma
13:18 min
10/15/2019
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Questions Session⎪Non-Ossifying Fibroma, Radial Tunnel Syndrome & Duchenne Muscular Dystrophy
  • Pathology
  • - Non-Ossifying Fibroma
23:55 min
11/8/2019
64 plays
0.0
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