slide 9+10 disorders of bone

8/3/2019 Slide 9+10 Disorders of Bone

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Dent 356-11Disorders of Bone I


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Inhereted and DevelopmentalDisorders of Bone

Osteogenesis Imperfecta

Osteopetrosis (Marble Bone Disease)

Cleidocranial Dysplasia (Cleidocranial Dysostosis)

Achondroplasia

Fibro-osseous Lesions

Fibrous Dysplasia of Bone

Cemento-osseous Dysplasia

Cherubism


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Osteogenesis Imperfecta

A heterogeneous group of relatedhereditary disorders.

The basic abnormality is a genetic defectin synthesis of type I collagen.


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Osteogenesis Imperfecta:Clinical Features

Characterized by weak bones with tendency tofracture.

The slender, long bones have narrow, poorlyformed cortices composed of immature wovenbone.

Fractures usually heal without trouble, butexuberant callus may form.


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Sclerae may appearblue because they are

so thin that the choroidshows through.

Joint hypermobility with

lax ligaments.


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Sclerae may appear blue because they are so thin thatthe choroid shows through.

There may be deafness due to distorted ear ossicles.

Joint hypermobility with lax ligaments.

Thin translucent skin.

Heart valve defects.


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Osteogenesis imperfecta is often associated withdentinogenesis imperfecta, especially in deciduousdentition.

It is thought that the two defects are carried byseparate but related genes.


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Dentinogenesisimperfecta may beassociated with some

cases.


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Four main types:

1. Type I (classic type): autosomal dominant, blue sclera, prematuredeafness, +/- dentinogenesis imperfecta.

2. Type II (perinatal lethal): autosomal dominant.

3. Type III (progressively deforming): autosomal dominant/ recessive,severely osteoporotic bone, progressive deformity, dentinogenesisimperfecta.

4. Type IV: autosomal dominant. Similar to type I but more severe,white sclera, +/- dentinogenesis imperfecta.


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Osteopetrosis (Marble Bone Disease):Clinical Features

Rare disease characterized by excessive density of allbones with obliteration of marrow cavities.

Secondary anemia, neutropenia, with susceptibility to

infections.*

Defect in osteoclast function results in failure of properremodeling of developing bone.

Abnormally dense bone is mechanically weak, sofractures are common.


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Osteopetrosis (Marble Bone Disease):Clinical Features

Jaws are composed of dense bone withreduced marrow spaces.

There may be delayed eruption of teeth.

Osteomyelitis is a common complication oftooth extraction.


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Osteopetrosis (Marble Bone Disease):Clinical Features*

Two basic patterns:

1. Malignant type:

Progressive. Autosomal recessive.

Occurs early in life.

Severe bone fragility

and malformations. Death usually before

puberty.

2. Benign type:

Autosomal dominant. Less severe.

Diagnosis may not bemade until late in life

and incidentally. Repeated fractures

following minor trauma.


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Osteopetrosis (Marble Bone Disease)Radiographic Features

Increased density of skeleton.

Lack of distinction betweencortical and medullar bone.

Marked density of base ofskull.

Mandible more involved thanmaxilla.

Roots of teeth may beinvisible.


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Osteopetrosis (Marble Bone Disease):Histopathologic Features

Thickened cortices.

Reduced marrow

cavities.

Persistence of wovenbone.

Marked lack of maturelamellar bone.


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Cleidocranial Dysplasia(Cleidocranial Dysostosis)

Autosomal dominant inheritance.

Abnormalities of many bones, particularlythe skull, jaws, and clavicles.

Dental abnormalities common.


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Cleidocranial Dysplasia (Cleidocranial Dysostosis):Clinical Features

Abnormalities of skull:

Fontanelles and suturestend to remain open.

Skull appears flat withprominent frontal, parietal,and occipital bones.

Nasal bridge is depressed.

Maxilla may beunderdeveloped with a high,narrow arched palate.
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Partial or complete

absence of claviclesallows shoulders to beapproximated until theymeet.
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Dental abnormalities: Deciduous dentition tends

to be retained with delayedor non-eruption ofpermanent dentition

because of multipleimpactions.

Supernumerary teeth anddentigerous cysts arecommon.

Roots tend to be thinnerthan normal. Secondary cementum is

sparse or absent on bothdentitions.


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Abnormalities of skull:

Fontanelles and sutures tend to remain open.

Skull appears flat with prominent frontal, parietal, and

occipital bones. Nasal bridge is depressed.

Partial or complete absence of clavicles allows shoulders

to be approximated until they meet in the midline.


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Dental abnormalities:

Maxilla may be underdeveloped with a high, narrow arched palate.

Deciduous dentition tends to be retained with delayed or non-eruption of permanent dentition because of multiple impactions.

Supernumerary teeth and dentigerous cysts are common.

Roots tend to be thinner than normal.

Secondary cementum is sparse or absent on both dentitions.


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Achondroplasia

Autosomal dominant, but some cases appear to bedue to spontaneous mutations.

Most common form of dwarfism.

Abnormality of endochondral ossification.

Absent or defective zone of provisional calcificationof cartilage in epiphyses and base of skull.


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Achondroplasia:Clinical Features

Trunk and head of normal size.

Limbs are excessively short.

Middle part of face is retrusive due to defectivegrowth of base of skull.

Severe malocclusion.


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Fibro-osseous Lesions

The term encompasses a variety of disorderswhich are characterized histologically byreplacement of normal bone by cellular fibrous

tissue within which varying amounts ofpredominantly woven bone and acellular islandsof mineralized tissue develop.

They cannot be distinguished by histology alone;clinical and radiographic features must beconsidered.


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Fibro-osseous lesion


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Fibro-osseous Lesions: Classification

A. Osseous dysplasia: Fibrous dysplasia

- monostotic- polyostotic

Cemento-osseous dysplasia:- periapical cemental dysplasia- focal cemento-osseous dysplasia- florid cemento-osseous dysplasia (gigantiform

dysplasia)

B. Benign neoplasia: Ossifying/ cemento-ossifying fibroma

M t ti Fib D l i f B


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Monostotic Fibrous Dysplasia of Bone:Clinical Features
http://www.usc.edu/hsc/dental/opfs/FO/003big.html


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Monostotic fibrous dysplasia

More common than polystotic

Limb, ribs, skull

Jaws Maxilla>mandible

When maxilla and other skull bones are involved itis called: craniofacial fibrous dysplasia

M t ti Fib D l i f B


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Monostotic Fibrous Dysplasia of Bone:Radiographic Features


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Monostotic Fibrous Dysplasia of Bone:


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Monostotic Fibrous Dysplasia of Bone:Clinical Features

1st

sign of disease is a gradually increasing, painlessswelling causing facial asymmetry.

Smooth, fusiform, and often more pronounced buccally

than lingually or palatally. In maxilla: from canine to tuberosity

Extension to maxillar sinus displacing orbital contents

Canine fossa is obliterated.

Doesnt cross suture lines

In mandible:

protuberance and increase in depth of the jaw.

failure of eruption of teeth


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Variable appearance, reflecting differing amounts of metaplastic bone formed.

Illdefined borders

Initially resemble cyst-like radiolucencies containing faintbony trabeculae.

With increasing trabeculation, they become mottled andeventually opaque.


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Polyostotic Fibrous Dysplasia of Bone:Clinical Features

2-3 times as common in females as males.

Variable distribution of lesions.

Bone of one limb, especially the lower, skull,vertebrae, ribs, and pelvis are also often involved.

Almost any combination can occur, but there istendency for segmental involvement and localizationto one limb or one side of body.



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The many delicate trabeculae give a ground-glass ororange-peel-stippling effect.

Roots may be separated Teeth may be displaced.


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Severe cases are usually diagnosed in childhoodbecause of associated deformities and pathologicalfractures.

May be accompanied by caf-au-lait melanotic spots onskin.*

Serum alkaline phosphatase may be elevated depending

on severity.*


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May present as part of McCune-Albright syndrome:

Rare, severe form.

Caf-au-lait skin pigmentation.

Precocious puberty in females.

Occasionally other endocrineabnormalities.

Pigmentation of oral mucosareported.

Fibrous Dysplasia of Bone:


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Fibrous Dysplasia of Bone:Histopathologic Features

Fibrous tissue containing islands and trabeculae ofwoven bone.

Fibrous tissue may be richly cellular or may consist of thick,interlacing collagen bundles.

Newly formed bony trabeculae are delicate and irregular(likened to Chinese characters).

May be thicker and blunter in long bones

Gradual fusion with surrouding bone



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http://www.usc.edu/hsc/dental/opfs/FO/013bb.html


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Spherical areas of calcification

resembling cemetum may bepresent.

Osteoblastic and osteoclasticactivity may be seen in relationshipto some trabeculae.

With time cellularity of fibrous tissuedecreases and the amount of boneincreases.as the lesion matures.

Aneurysmal bone cyst.+-

http://www.usc.edu/hsc/dental/opfs/FO/017bb.htmlhttp://www.usc.edu/hsc/dental/opfs/FO/016bb.html


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Appearances of jaw lesions are more variable than in otherbones.

In jaw lesions, trabeculae may be thicker and blunterthan in long bones.

Spherical areas of calcification resembling cemetum maybe present.

Osteoblastic and osteoclastic activity may be seen inrelationship to some trabeculae.


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Fibrous Dysplasia of Bone:Etiology & Behavior

Pathogenesis is complex

It is not inherited but considered a developmentaldefect.

Caused by mutation occurring in fetal (polyostotic) orpostnatal (monostotic) life.

Mutation in GNAS 1 gene which encodes for astimulatory protein.


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Fibrous Dysplasia of Bone:Etiology & Behavior A few cases of malignant transformation have been

reported, usually to fibrosarcoma.

Some of those cases followed radiotherapy which isnow not an unacceptable treatment.

Majority of cases are treated by conservative surgicalremoval to reduce deformity only.

The lesions tend to expand mainly during the period ofactive skeletal growth and become quiescent in adult life.

C D l i


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Encompasses osseous dysplasias localized to thejaws, particularly tooth-bearing areas.

It incorporates:- periapical Cemental Dysplasia

- focal Cemento-osseous Dysplasia

- florid Cemento-osseous Dysplasia

They are considered to be different clinicalpresentations of the same disorder.


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Shows the characteristic features of a fibro-osseouslesion

The radiographic features reflect the extent of

mineralization and may be radiolucent, mixed, orradiopaque.

More prevalent in women than men.

Majority of patients >30 years of age.

Predominant in mandible.


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Presents a range of appearances:

Periapical cemental dysplasia: multiple small lesions

associated with apical areas of mandibular incisors.

Florid Cemento-osseous Dysplasia: Multiple largelesions involving one or more quadrants in one or both

jaws.


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Florid Cemento-osseous Dysplasia:Radiographic Features

Dense, lobular,radiopaque masses.

Ossifying Fibroma
http://www.usc.edu/hsc/dental/opfs/FO/050big.htmlhttp://www.usc.edu/hsc/dental/opfs/FO/050big.html


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Ossifying Fibroma(cemento-ossifying fibroma)

Benign neoplasm, true neoplasm

Fibrous tissue, bone, rounded calcified

bodies Demarcated with occasional

encapsulation


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Ossifying fibroma


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Ossifying Fibroma


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Ossifying Fibroma

Clinically:

Swelling, progressively enlarging

Mandible Sinonasal complex and orbit

Female more

Radiographically: Well defined RL, RL and RO, RO


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Ossifying Fibroma


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Ossifying Fibroma

Histopathology:

Fibrous tissue, well demarcated, trabeculae ofbone, osteoblastic rimming

Acellular calcified material (resemblingcementum)

If predominant it is called psammomatoid

variant (sand-like) D/D: fibrous dysplasia and cemento-osseous

dysplasia


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Psammomatoid ossifying


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Psammomatoid ossifyingfibroma

Cementum like bodies


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Ossifying fibroma

Ossifying Fibroma


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Ossifying Fibroma

Prognosis:

Slowly growing or rapidly growing

May be associated with hereditary hyperparathyroidism

Juvenile ossifying fibroma Richly cellula, mitotically active, immature woven bone

D/D: osteosarcoma

30-60% recurrence rate


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Cherubism

Rare disorder of bone, inherited in autosomaldominant pattern with variable expressivity.

Thought to be related to a mutation in geneassociated with fibroblast growth factor receptor3 (FGFR3).


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Cherubism: Clinical Features

Painless bilateral swellings of the jaws appear between ages 2-4 years.

always involve the mandible either alone or in combination with the maxilla.

They enlarge rapidly up to age 7 years then become static and startto regress.

Progressive reduction in deformity as the patient passes frompuberty into adult life.

Cosmetic surgery is often needed to deal with residual deformity.


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Cherubism

eyes upturned toheaven appearance.

Reactive hyperplasia of

submandibular lymphnodes adds to facialfullness.


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Cherubism: Radiographic Features

Sharply defined, multilocularradiolucencies.

Expansion and thinning ofcortical plates, evenperforation.

Mandibular lesions appear tobegin near the angle andspread to involve the body andramus.

Maxillary lesions are oftenconfined to tuberosities, butsinus may be obliterated.


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Dental abnormalities:

premature loss ofdeciduous teeth

displacement, lack oferuption, and failure ofdevelopment of manypermanent teeth.


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Cherubism: Histopathologic Features

Cellular and vascular fibrous tissue containing varyingamounts of multinucleated giant cells.

similar to other giant cell lesions of the jaws, and

differentiation between them requires clinical andradiographic information.

As the activity of the lesion decreases, it becomes morefibrous, giant cell number diminishes, metaplastic bone

is deposited.


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Primary Hyperparathyroidism

Seen predominantly in middle-aged women.

Excessive parathormone secretion may result froman adenoma or occasionally adenocarcinoma or

idiopathic hyperplasia of parathyroid gland.

Functions of parathyroid hormone includestimulation of :

1. Intestinal absorption of calcium.2. Reabsorption of calcium by renal tubules

3. Bone resorption by osteoclasts.


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Primary Hyperparathyroidism

Thus, excessive hormone secretionresults in:

1. Hypercalcemia.

2. Hypercalciuria.

3. Metastatic calcification in urinary tract,

blood vessel walls and lungs.

Primary Hyperparathyroidism:


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Primary Hyperparathyroidism:Clinical Features*

Severe cases may variably be associated with:1. Bone pain.2. Bone cysts (osteitis fibrosa cystica).3. Pathological fractures.4. Brown tumors.5. Renal colics due to stones.

6. Mental changes including depression, emotionalliability, poor mentation, and memory defects.

7. Increased incidence of peptic ulcer.8. Chronic pancreatitis.9. Hypertension.



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Primary Hyperparathyroidism:Clinical Features*

Biochemical changes have to be demonstrated to

confirm diagnosis. They are:

1. Elevated parathomone level.2. Increased serum calcium level.

3. Reduced serum phosphate level.

4. Increased urinary excretion of calcium andphosphate

5. There may be elevated alkaline phosphatase.



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Primary Hyperparathyroidism:Histopathologic Features

Increased osteoclastic activity throughout the skeleton.

Fibrosis of marrow (osteitis fibrosa).

Occasionally, focal areas of bone resorption result information of lesions called brown tumors.


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Brown tumors are identical to other giant cell lesions ofthe jaws.

They consist of large numbers of multinucleated,

osteoclast-like giant cells scattered in a highly cellular,vascular fibroblastic connective tissue stroma.

There is much hemosiderin pigment present, hence the

brown color seen grossly.


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Very rarely brown tumor may occur in relation to theperiosteum and may represent clinically on the gingiva,similar to giant cell epulis (peripheral giant cellgranuloma).

Possibility of hyperparathyroidism should be consideredin patients with multiple or recurrent central or peripheralgiant cell granulomas of the jaws.

Biochemical changes have to be demonstrated toconfirm diagnosis.



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Primary Hyperparathyroidism:Radiographic Features

May show no detectable changes or generalizedosteoporosis.

Partial loss of lamina dura around roots of teeth may

occur.



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Primary Hyperparathyroidism:Radiographic Features

Brown tumors present as sharply defined, roundor oval radiolucent areas.

They may be multilocular.

They occur more frequently in the mandible thanin the maxilla.


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Secondary Hyperparathyroidism

Occurs in response to:

1. chronic hypocalcemia most frequently due tochronic renal failure,

2. in association with rickets and osteomalacia.

Bone changes are complex and are a mixture ofthose associated with osteomalacia andhyperparathyroidism.

Involvement of the jaws has been reported.


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Giant Cell Lesions of Bone

Central giant cell granuloma

Giant cell tumor of bone

Giant cell lesions of hyperparathyroidism(brown tumor)

Cherubism


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Central Giant Cell Granuloma


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Central Giant Cell GranulomaClinical Features

Probably reactive and not neoplastic

Reactive to heamodynamic changes: traumaor heamorrhage

Most common in young adults

Female predominance

Only occurs in the jaws

More common in mandible (~70%)

Involves anterior part of the jaws


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Clinically: Swelling of bone

Rapid growth or

symptom less

Non-aggressive lesions: asymptomatic, slowgrowth, does not perforate cortex, lowrecurrence

Aggressive lesions: rapid growth, perforatescortex, higher recurrence

Most CGCG are non-aggressive



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Ce t a G a t Ce G a u o aRadiographic Features

Well-demarcated or poorly definedradiolucent lesion

Unilocular or multilocular

Can cause thinning, expansion orperforation of cortical plate

Root displacement or resorption.


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Microscopic Features

Fibrous connective tissue, multinucleatedgiant cells, hemorrhage and hemosiderin


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1

2


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Treatment and Prognosis

Simple enucleation and curettage

Recurrence rate following curettage isabout 15-20%

Long-term prognosis is good.

Need to exclude hyperparathyroidism


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True Giant Cell Tumor of Bone

Giant cell tumors occur in long bones, veryrare in Jaws

more aggressive

higher recurrence rate may metastasize in 10% of cases

distinct from central giant cell granuloma

and represents a true neoplasm.

slide 9+10 disorders of bone

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