Fibrous Dysplasia

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Fibrous Dysplasia

• Jan M. Eckermann, MD
• Department of Neurosurgery

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Definition

• Benign condition in which normal bone is replaced
  by fibrous connective tissue due to a defect in
  osteoblast differentiation and maturation

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Epidemiology

• Incidence not known
• Females gt males
• No race predilection
• Initial symptoms manifest age 3-15
• Not heritable
• Questionable genetic transformation
• Malignant transformation in lt 1

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Variations

• Cystic (21)
• Radiolucency surrounded by solid rim
• Sclerotic (23)
• Dense and homogenous
• Mixed (56)
• Ground glass appearance

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Variations, contd

• Monostotic
• Most common
• 25 involve head and neck
• Polyostotic
• 15 of cases
• 50 involve head and neck

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Whereyouat?
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Images

• Left temporal bone involvement

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Images

• Right temporal bone lesion

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Images
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Presentation

• Local pain
• Swelling
• Abnormal pigmentation
• CN compression
• Spontaneous scalp hemorrhage
• Part of McCune-Albrights syndrome

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McCune-Albrights Syndrome

• Polyostotic fibrous dysplasia
• Café-au-lait spots
• Endocrinopathology
• Hyperthyroidism
• Precocious puberty in females

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Imaging

• Plain radiography is first line
• Computed tomography for complex regions

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Histology

• Fibroblasts within woven cancellous bone

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Whereyouat?
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Differential Diagnosis

• Eosinophilic granuloma
• Nonossifying fibroma
• Bone hemangioma
• Hyperparathyroidism
• Pagets disease
• Browns tumor
• Aneurysmal bone cyst

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Treatment

• No available cure
• Curettage
• Cranioplasty
• Calcitonin

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The One Slide To Remember

• Genetic, non-heritable disorder
• lt1 transformation to malignancy
• Treatment is curretage or cranioplasty

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Whereyouat?
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References

• Greenberg, M. Handbook of Neurosurgery 6th
  Edition. Thieme New York 2006
• Kaye AH, Black P McL. Operative Neurosurgery Vol
  2. Harcourt Publishing New York 2000
• Dal Cin P, Sciot R, Spelenberg F, et al.
  Chromosome Aberration in Fibrous Dysplasia.
  Cancer Genet Cytegent 1994 Oct1577(2) 114-7