1. FIBRO-OSSEOUS LESIONS
dr shabeel pn

2. INTRODUCTION
The term ‘FOL’ is a generic designation of a group of bone disorders characterized by the replacement of bone by a benign connective tissue matrix that displays varying degrees of mineralization in the form of woven bone or cementum.
Group include:
developmental lesions
reactive / dysplastic lesions
neoplastic lesions
Dr.Haris PS/OMR

3. Importance of Specific Diagnosis
The histopathology of all FOL is identical, although they range widely in clinical behavior.
More specific diagnosis is important because the treatment of these pathoses varies from none to surgical recontouring to complete removal.
Dr.Haris PS/OMR

4. CLASSIFICATION FOL of medullary bone origin FOL of PDL origin FD
Fibro osteoma
Cherubism
Juvenile OF
Giant cell tumor
ABC
Jaw lesions in hyperparathyroidism
Paget’s disease
FOL of PDL origin
Fibroma CF OF
COF
Dr.Haris PS/OMR

5. WHO classification of Odontogenic tumors (2nd ed, 1992)
(a) Fibrous dysplasia
(b) Cemento – ossifying fibroma
- Spectrum of COF: CF-COF-OF
- Juvenile Ossifying Fibroma
WHO type
Psammous type
(c) Cemento-osseous dysplasia
-PCOD
-Focal COD
-Florid COD
-Familial gigantiform cementoma.
Dr.Haris PS/OMR

6. Modified WHO classification (Speight and Carlos)
Fibrous dysplasia
Monostotic
Polyostotic
Craniofacial
Osseous dysplasias
PCOD
Focal COD
Florid COD
Familial gigantiform cementoma
Ossifying fibromas
Conventional ossifying fibroma
Juvenile trabecular (WHO type) OF
Juvenile psammomatoid OF
Dr.Haris PS/OMR

7. FIBROUS DYSPLASIA Developmental or hamartomatous condition
Unknown etiology
Characterized by proliferation of cellular fibrous connective tissue mixed with bony trabeculae
Sporadic condition, resulting from post zygotic mutation in GNAS– 1 gene
Clinical severity depends on the point of time during embryonic, fetal or post natal life at which mutation of GNAS – 1 occurs
Dr.Haris PS/OMR

8. Clinical Features Monostotic fibrous dysplasia Limited to single bone
80 – 85% of all cases
Jaws among most common sites
Diagnosed during second decade
No sex predilection
Painless swelling – most common feature.
Slow growth, become static with skeletal growth completion
Dr.Haris PS/OMR

9. Craniofacial fibrous dysplasia Peculiar form affecting skull bones
Not restricted to single bone, but confined to single anatomic site.
Primarily affect maxillae, but may cross sutures into sphenoid, zygoma, frontonasal bones and base of skull.
Dr.Haris PS/OMR

10. Involvement of two or more bones other than craniofacial bones
Polyostotic FD
Involvement of two or more bones other than craniofacial bones
Number of bones – a few to 75% of skeleton
With café au lait (coffee with milk) pigmentation, Jaffe – Lichtenstein syndrome
With café au lait pigmentations and multiple endocrinopathies – sexual precocity, pituitary adenoma or hyperthyroidism, McCune – Albright syndrome
Dr.Haris PS/OMR

11. May present with facial asymmetry
Clinical features usually dominated by symptoms related to long bone lesions – Pathologic fractures
Length discrepancy due to involvement of upper portion of femur (hockey stick deformity)
Café au lait pigmentation – generally unilateral tan macules on the trunk and thighs.
- May be congenital
- Oral cavity can be involved
- Margin typically irregular (Coastline of Maine)
Dr.Haris PS/OMR

12. Radiographic Features
Site – Most often involves maxilla
Posterior aspect. Unilateral
Periphery ill defined. Gradual blending
Internal structure.
Variation pronounced is maxilla
More uniform in mandible
Dr.Haris PS/OMR

13. Mixed radiolucent-radiopaque Heterogenous pattern
Orange peel – pathognomonic
Ground glass
Radiopaque – cottonwool or diffuse
Dr.Haris PS/OMR

14. Effect on surrounding structures Thinning of cortex
Displacement of antral walls
Loss of lamina dura
Displacement of teeth
Interference with normal eruption
Inferior alveolar canal – displaced superiorly / inferiorly
Superior displacement – unique to FD.
Dr.Haris PS/OMR

15. CT To define extent of involvement of cranial base. 34 – 513 HU
Heterogeneous pattern of CT densities associated with scattered or confluent islands of bone formation
Dr.Haris PS/OMR

16. MRI Intermediate signal on T1 weighted and proton weighted images
Heterogenous hypointense signal of T2 weighted scan
Moderate to significant contrast enhancement after i.v. Gd contrast infusion.
Dr.Haris PS/OMR

17. Management and Prognosis
Small lesions can be resected entirely
Most lesion stabilize with skeletal maturation
Surgical recontouring after skeletal maturation
Osteosarcoma-especially in those who received radiation.
Dr.Haris PS/OMR