Bone Pathology I - fibro-osseous lesions (fibro-osseous dysplasia) Flashcards
What is Fibro-osseous Lesions?
- Normal bone replaced by cellular fibrous tissue with amounts of woven bone and/or acellular islands of mineralized tissue.
Fibrous tissue can have some trabecular bone formation inside or cementum formation inside
2 types of fibro-osseous lesions?
Fibro-osseous dysplasias:
Cemento-osseous dysplasia:
Cemento-osseous dysplasia?
- fibro-osseous lesions
- Focal cemento-osseous dysplasia.
- Periapical cemental dysplasia.
- Florid cemento-osseous.
- Gigantiform dysplasia.
2 types of Fibro-osseous dysplasias?
- fibro-osseous lesions
- Monostotic fibrous dysplasia.
- Polystotic fibrous dysplasia.
- dependent on how they spread
mono- affects 1 bone
poly - affects multiple bones
Monostotic Fibrous Dysplasia occurs where?
most common bones affected Limb, rib, skull particularly
Jaw bones.
- Maxillary lesions are more
common than mandibular
What age does monostotic fibrous dysplasia occur?
Childhood and adolescence
What is monostotic fibrous dysplasia?
- Cessation of bone growth
once skeletal growth stops. - Reactivation of lesions during
pregnancy.
Clinical presentataion of monostotic fibrous dysplasia?
12 marks
- Gradual painless bony swelling.
- Facial asymmetry.
- More pronounced buccally.
- Increased prominence of the
cheek in maxillary lesion. - Displacement of teeth
eye can be protruded form normal location if in the maxilla
- Sinus, zygomatic process and floor of the orbit
(displacement of the contents) involvement. - In case of rapid growth, exophthalmos and proptosis.
- mandibular lesions in the molar and premolar regions
- increased jaw depth if the lower border is involved
- malignant, tipping or displacement of teeth
- failure of eruption of involved teeth - effects younger pts, affect eruption
Differential diagnosis? (Periapical Cemental Dysplasia)
Periapical granuloma
Radicular cysts
Periapical abscess
Differential diagnosis? (Florid Osseous Dysplasia)
Odontogenic keratocysts
Name the cemeto-osseous dysplasia and what they affect?
1) focal cemento-osseous dysplasia
- 1 tooth anterior region
2) periapical cemental dysplasia
- multiple teeth, mosty anterior teeth
3) florid cemento-osseous
- whole jaw or whole quadrant of jaw
what is more common monostotic or polystotic fibrous dysplasia?
monostotic
maxilla or mandible more commonly affected by monostotic fibrous dysplasia?
maxilla
if multiple bones are affected by monostotic fibrous dysplasia, what is this called?
craniofacial fibrous dysplasia
When does monostotic fibrous dysplasia stop and when can it restart?
cessation of bone growth once skeletal growth stops
reactivation during pregnancy or contraceptive pill
usually self-limiting
what is occurring here?
normal bone is replaced by fibrous tissue
distorts bone (swelling)
What has occurred here?
monostotic fibrous dysplasia
displacement of teeth
radiographic appearance of monostotic fibrous dysplasia?
ill defined borders
gradual transition to normal bone
- earlier lesions radiolucent as bone replaced by fibrous tissue
- the mixed fibrous and been formation
- later radiopaque as lesion and bone formation stop
appearance ranges form radiolucent to mottled to radiopaque
ground glass orange peel or cotton-wool appearance
what disease?
monostotic fibrous dysplasia
polyostotic fibrous dysplasia affects men or women more?
females more 3 times more
what bones does polyostotic fibrous dysplasia affect?
bones of lower limbs, skull, vertebrae, ribs and pelvis
do lesions for polystotic fibrous dysplasia arise in both sides of the body?
often only arise in 1 side
how can severe cases of polystotic fibrous dysplasia present?
present early due to bony deformities and pathological fractures
what syndrome is polystotic fibrous dysplasia associated with?
McCune- albright syndrome
affects mainly females
skin pigmentation
hyperfunction of endocrine glands
precocious puberty
histopathology of fibrous dysplasia?
- fibrous tissue with islands of woven bone replaces normal bone
- foci of lamellar bone might be seen
- spheroidal areas of acellular calcified tissue
- fibrous tissue may be cellular or consists of interlacing collagen fibres
- Chinese characters
- trabeculae in jaw lesions may be thicker and blunter
what disease has Chinese characters?
fibrous dysplasia (fibro-osseous lesions)
irregular trabeculae
what disease is shown?
fibrous dysplasia
highly cellular fibrous tissue
irregular trabeculae
pathology of fibrous dysplasia?
at the borders, the abnormal bones fuses with surrounding normal bone
(main difference from ossifying fibroma)
as pt become older and bone stops growing - fibrous issue becomes less cellular and more bone formation and becomes more structure bone formation
woven bone remodelled into lamellar bone as bone matures
problem with fibrous dysplasia?
lesiosn fuse with normal bone
difficult to iodentify bornders
why it hard to identify borders of fibrous dysplasia?
as lesions fuse with normal bone
fibrous dysplasia vs ossifying fibroma?
fibrous dysplasia at the borders, the abnormal bone fuses with surrounding normal bone
look exactly the same as fibrous dysplasia but has well defined borders
when can fibrous dysplasia become malignant?
few cases are malignant (fibrosarcoma)
malignant transformation following radiotherapy
how to remove fibrous dysplasia?
surgical removal
when do fibrous dysplasia lesions expand?
period of growth
- cessation of growth in adulthood
aetiology of fibrous dysplasia?
complex pathogenesis
GNAS1 is involved - protein involved in bone turnover
management of fibrous dysplasia?
after growth cessation
conservative surgical removal
or antibody therapy to target RANKL, which is over-expressed in fibrous dysplasia as a result if the GNAS1 mutation
