6. Fibro-Osseous Lesions of Bone Flashcards
What is the common histology of Fibro-Osseous Lesions of Bone?
Spindly cellular, fibrous stroma, containing variable amounts of some mineralized material (bone, cementum, or combo), not dystrophic calcification
What is the age of pts with Fibrous Dysplasia?
1st – 2nd decade
- Once it forms it isn’t going away, can see it in older people, it just developed a while ago
- Grows with pt, peaking in puberty, it won’t regress after puberty, it stays the same size for life
Where does Fibrous Dysplasia occur?
ANY BONE in the body
Posterior jaws favored if it occurs in the jaws
What is the pathogenesis of Fibrous Dysplasia?
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Developmental condition = somatic mutation in G protein (GNAS1):
- G proteins act as an on/off switch, responsible for bone production, here it remains on
- When it should stop bone production it doesn’t, so it keeps on producing bone
- But it doesn’t mineralize bone, so the bone being produced continuously is soft, osteoid-like bone, that does not mature but keeps on growing
What form of Fibrous Dysplasia occurs when the G-protein mutation occurs postnatally (as an infant)?
Monostotic Fibrous Dysplasia
Only 1 bone is affected
What form of Fibrous Dysplasia occurs when the G-protein mutation occurs in early embryonic life?
Polyostotic Fibrous Dysplasia
The single mutated cell is destined to become multiple different bones
What form of Fibrous Dysplasia occurs when the G-protein mutation occurs super early in embryonic life?
Albright Syndrome
- The same G-protein also controls:
- Melanin production - Cafe-au-lait spots - Coast of Maine
- Endocrine secretions - precocious puberty in females
What is the appearence of Monostotic Fibrous Dysplasia?
Doesn’t cross the midline
What is the severe expression of Polyostotic FIbrous Dysplasia?
Albright Syndrome
- Fibrous Dysplasia of many bones
- Precocious puberty in female
- Cafe-au-lait spots - coat of maine (jagged)
What is Jaffe Lichenstein Syndrome?
Milder Albright Syndrome
No precocious puberty in females
What are the characteristics of Juvenile Aggressive Fibrous Dysplasia? (5)
- Young kids
- Rapid swelling
- Gross deformity = Leontiasis Ostea
- Also in Paget’s Disease
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Destruction of tooth buds, it will move teeth
- This doesn’t occur in regular FD
-
Interference with swallowing and breathing
- Surgery must be done
What are the 3 ways Fibrous Dysplasia can appear radiographically?
- Ground Glass RO
- Multi-locular RL
- Mixed RL with Mottled RO
What are the radiological findings in Fibrous Dysplasia? (4)
-
Fusiform, tapered expansion
- It can expand enough to cause facial deformity
- Ground glass expansion of orbit and obliteration of the sinus
- Diffuse, ill-defined, blending margins
-
Involves and incorporates cortical bone and lamina dura
- Obliterates cortex, you can’t see the outline of the mandible, it has been incorporated - appears porous
- Lose lamina dura
-
Multi-focal Growth
- Teeth are not displaced relative to each other, like in a neoplasm
What is the Histological presentation of Fibrous Dysplasia? (4)
- Immature woven bone forming directly from stroma, and forming irregular trabecular patterns = Chinese Characters
- Don’t see osteoblasts producing it
- Maturation Arrest - bone never matures, stays soft
- Lamina dura replaced by dysplastic bone
What is the histologic features of Craniofacial Complex Fibrous Dysplasia?
- It is a polyostotic fibrous dysplasia that acts differently
- There is so much remodeling in the facial area that eventually the bone matures:
- Start to get lamellaer bone and osteoblastic rimming
- Lose the ability to discriminate it from Ossifying Fibroma or Osseous Dysplasia via biopsy
- if its next to a tooth you can differentiate FD - lamina dura is incorporated/replaced with dysplastic bone
What is the treatment for Fibrous Dysplasia?
-
Delayed surgical recontouring of deformity until after puberty, or it will regrow more aggressively
- Bone is easily shaved “carboard consistency”
-
Orthodontics is easily accomplish
- Teeth move through fibrous dysplastic bone like butter
In Fibrous Dysplasia what can occur with multiple surgeries and radiation?
-
Sarcomatous Transformation of fibrous dysplasia bone into a:
- Osteosarcoma
- Fibrosarcoma
What lesion is the rarest of the fibro-osseous group?
Ossifying Fibroma
What population is affected by Ossifying Fibroma?
Females 3rd - 4th decade
Where do Ossifying Fibromas occur?
ONLY IN JAWS
Prefers mandibular premolars + molars
What is the pathogenesis of Ossifying Fibroma?
True benign neoplasm of medullary bone
What is the clinical presentation of an Ossifying Fibroma?
Single, painless, oval, bony swelling
What is the form of Ossifying Fibroma that occurs in kids?
Juvenile Active Form of Ossifying Fibroma
What are the characteristics of the Junvenile Active form of Ossifying Fibroma? (4)
- Slowly expansile mass in children
- Mostly in the maxilla
- Normally Ossifying Fibroma is in the mandible
- RL Cannonball
- Shells out and rarely recurs
What are the characteristics of Ossifying Fibroma that are radiographically distinguishable from Fibrous Dysplasia? (4)
- Begins as a well-demarcated, ovoid RL
- Increasing RO with age
- Diverges roots
-
Thins and bulges cortex (dissolves cortex by pressure)
- Not incorporating the cortex like in Fibrous Dysplasia
What is the radiographic differential diagnosis for Ossifying Fibroma when it is RL? (3)
- OKC
- Periapical Cyst
- Residual Cyst
What is the radiographic differential diagnosis for Ossifying Fibroma when it is mixed RL/RO, encroaching cortex, not incorporating it?
Odontogenic Tumors + Cysts with RO
What is the histology of Ossifying Fibroma? (4)
- Fibrous capsule, that’s how you remove it in a smaller one
- Very cellular, well demarcated border
- Begins to acquire cementum-like calcified droplets (rounded, with concentric reversal lines)
- Will produces bone, cementum & combinations of both, become indistinguishable from other Fibro-Osseous Lesions
What is the treatment and prognosis for Ossifying Fibroma?
Shells out easily along its capsule
Rarely recurs
What is the most common Fibro-Osseous Lesion?
Cemento-Osseous Dysplasia
What is the pathogenesis of Cemento-Osseous Dysplasia?
Reactive process, but not sure what to
What is the histology for all 3 subtypes of COD? (2)
- Droplets of cementum & spicules of bone develop in cellular fibrous stroma
- Eventually enlarging & coalescing as the lesion matures into a ginger-root pattern
What population does Periapical COD (Cementoma) occur in?
80% in black females > 20 yrs
NEVER in White Males
What is the location of a Periapical COD?
Must start as periapical to mandibular anterior’s
- Can be individual or coalescing around several apices
- Have to have teeth & be around apices
What is the Clinical Presentation of Periapical COD? (4)
- Once formed, will not resorb even w/ extraction
- Asymptomatic
- Assoc teeth are usually vital & seldom have restorations
- Teeth can be non-vital but you can’t make the dx
- Don’t have to be individual, can coalesce
What is the radiographic appearance of the Periapical Cementoma?
- Early RL Stage, when there is no RO
- Stage 2 Cementoma, when RO start to form, where you get ground glass appearance or multiple chunks of RO
- Stage 3 Cementoma, predominantly RO, with maybe a thin rim of RL
What population is affected by Florid COD?
80% in black females > 20 yrs
Where is Florid Osseous Dysplasia found?
- Multifocal - periapical to multiple mandibular teeth
-
Above the mandibular canal
- So does TBC
What disease is associated with Traumatic Bone Cyst, and is the only time it can be seen in Adults?
Florid Osseous Dysplasia
What is the clinical presentation of Florid COD? (2)
- Lesion remains even when the associated tooth is extracted
-
Symptomatic
- There is so much cemental material produced that it can cause swelling + sequestration
- Only COD that is symptomatic
What complications can occur with Florid OD?
- Sclerotic cementum is pathologic & can’t resorb
- If teeth are extracted or pt needs denture, the cemental masses become exposed & infected causing dull ache & Osteomyelitis
What is the radiographic appearance of Florid COD? (3)
- Lesions most visible around mandibular molar roots
- Multiple areas of periapical RL with or without jagged RO
- Induces Hypercementosis
What is the treatment for Florid OD? (3)
Asymptomatic - don’t treat
- Inform pt to take good care of their teeth, b/c if you need extractions & dentures the condition that you have now that is asymptomatic can become symptomatic
- Dentures can cause Jaw Enlargement or Osteomyelitis
- Osteomyelitis from dentures treated with antibiotics + debridement
What population does Focal COD affect?
Black + white females > 20 yrs
Where is Focal COD found?
- Forms in edentulous mandibular extraction sites
- Only one that is NOT periapical
- Individual
How does Focal COD differ from the other Cemento-Osseous Dysplasia? (4)
- Only one seen regularly in white females
- NOT Periapical
- Always a Single Lesion
- Edentulous site following extraction
What are the similarities of Focal COD to the other Cemento-Osseous Dysplasias? (4)
- Seen almost exclusively in middle aged females
- Most cases in mandible
- X-ray shows RL, mixed, or RO
- Identical histology = gingger root pattern
How is Focal COD different from Ossifying Fibroma? (3)
Focal COD…
- Remains small < 1.5cm
- Doesn’t encroach on cortex
- At surgery it is gritty & vascular & doesn’t separate easily
- Whereas OF shells out like a marble
What are the similarities between Focal COD and Ossifying Fibroma? (5)
- Well-demarcated RL, mixed lesion or RO
- Mandible
- Not assoc with teeth
- Females
- Identical Histology
What is the treatment for Focal COD?
Difficult surgical removal
- Gritty & vascular
- Doesn’t shell out easily like ossifying fibroma
