Fibro-Osseous Lesions Flashcards
What are fibro-osseous lesions characterised by?
Progressive replacement of bone by fibrous tissues followed by partial maturation back towards lamellar bone.
What are the shared histological features of fibro-osseous lesions?
- Areas of fibrous connective tissues replacing the normal bone
- Within this is areas of new bone formation
What is a cemento-ossifying fibroma clinically?
- This is a benign neoplasm that affects the jaws
- It appears to arise from mesenchymal blast cells of the PDL
- The tumour has the potential to form fibrous tissue, cementum and bone
- 2-3X more common in females
- Affects the facial bones, esp the mandible
- Can cause bony expansion, facial asymmetry and tooth displacement
What is the radiology of a cemento-ossifying fibroma?
- Early stage radiolucent (fibrous tissue) or with a faint radio-opaque pattern
- Typically appears as mixed radio-opaque pattern with wispy trabeculae to a more speckles or flocculent patten as more calcification is laid down
- Later stages have a more amorphous radio-opaque appearance
Answer these questions about a cemento - ossifying fibroma:
Shape?
Size?
Margin / outline?
Effect on surrounding structures?
Shape = irregularly rounded
Size = often small but can be large esp when the maxilla or sinuses aere affected
Margin = well defined, thin encapsulating radio-lucent line due to fibrous capsule
Effect = tooth displacement, displacement of ID canal, thinning and expansion of the bone cortices
What are the radiological differential diagnosis of a cemento-ossifying fibroma?
- Fibrous dysplasia (but this has a less defined margin)
- Cementoblastoma
- Giant cell granuloma, calcifying odontogenic cyst
What is the treatment for a cemento-ossifying fibroma?
Surgical excision with or without surgical reconstruction
What is the definition of a benign cemtento-blastoma?
Will it cause pain?
A slow - growing, benign, mesenchymal neoplasm consisting of mostly cementum like tissue.
It is attached to and grows around a tooth root.
Male > female.
NO. May be asymptomatic or cause discomfort.
What does a cemento-blastoma look like on X ray?
- attached or fused to tooth roots
- commonly causes root resorption
- mostly radio-opaque, peripheral radio-lucent margin
- round shape, outline is well defined
- may enlarge sufficiently to produce jaw expansion
What is fibrous dysplasia caused by? What are the clinical features?
- Caused by mutation in GNAS1 gene which leads to formation of dysplastic bone
- Normal bone is replaced by cellular fibrous tissue containing islands of trabecule of metaplastic bone
- Clinical Features: commonly diagnosed at 10, common in posterior maxilla and zygomatic process, usually results as a unilateral swelling, compression of nerves leads to anosmia, deafness and blindness
What are the radiological features of fibrous dysplasia?
- Depends on the state of maturing and the proportion of fibrous tissue
- Early lesions are more radiolucent than mature lesions
- Radio-opaque pattern varies and can be granular, ground glass, stippled, wispy or amorphous
- Typical appearance is stippled
- Margin is ill defined with a gradual bleeding with the normal adjacent bone
- Effects: lamina dura around teeth become hard to identify, may displace teeth occasionally, rarely root resorption, jaw expansion is common with thin cortical plates, expansion into the maxillary sinus
What are the histological features of fibrous dysplasia?
- Not diagnostic
- Bone replaces fibrous tissue containing woven bone trabeculae in C, S and Y shapes
- Gradual maturation from woven to heavily mineralised lamellae bone
What is cemento-osseous dysplasia and what are the three types?
3 types: periapical, focal, florid
- Normal bone is replaced by fibrous tissue with subsequent deposition of amorphous bone
What is periapical cemento-osseous dysplasia?
- Starts during third decade
- Affects several teeth at the same time
- Slowly changes over many years
- Typically affects lower incisors / first molars
- Asymptomatic, incidental finding
- Teeth remain vital
- No treatment required other than periodic managment
What is focal cemento-osseous dysplasia?
- Same as periapical cemento-osseous dysplasia but presents as a single lesion in one location
- Same clinical and radiological features as cemento-osseous dysplasia
- Margin of radiolucency is well defined with vital teeth
