Inherited & Developmental Disorders

8/3/2019 Inherited & Developmental Disorders

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1. Osteogenesis imperfecta 2.Osteopetrosis 3. Cleidocranial Dysplasia

Intro A heterogenous gp of related hereditaryd/o

Rare,excessive density of all bones withobliteration of marrow cavities+2Anemia+Neutropenia

AD,abnormalities of bones:skull,jaws and clavicle

EtiologyGenetic defect in synthesis oftype 1Collagen-2 defects r carried by separate but relatedgenes.

Defect in osteoclast fxn,results in failure ofproper remodeling of developing bone

Mutations to theRUNX2 gene(previously CBFA1)

Clinical Features 1. Sclerae may appear blue

because they are so thin that thechoroid shows through.

2. Joint hypermobility with laxligaments.

3. Dentinogenesis imperfecta

(DI)may be associated with somecases

4. Weak bones with fracturetendency

5. The slender,long bone have:Narrow,poorly formed cortices

composed of immature woven bone

6. Deafness from distorted earossicles

7. Translucent,thin skin

1. Dense boneweakfracture

2. Jaws are coposed of dense bone+ reduced marrow spaces

3. Tooth eruption delayed

Two basic patterns:

1.Benign type 2.Malignant type:

Autosomal

dominant

Less severe

Diagnosis may notbe made until latein life andincidentally.

Repeated fracturesfollowing minortrauma

Autosomal

recessive-Progressive

Severe bonefragility andMalformationsOccurs early in life

Death usuallybefore puberty

Abnormalities of skull:1. Fontanelles and sutures tend to remain open.2. Skull appears flat with prominent frontal, parietal,

and occipital bones.3. Nasal bridge is depressed.4. Maxilla may be underdeveloped with a high, narrow

arched palate.

Partial or complete absence of clavicles allowsshoulders to be approximated until they meet.

Dental abnormalities:1. Deciduous dentition tends to be retained

with delayed or non-eruption of permanentdentition because of multiple impactions.

2. Supernumerary teeth and dentigerous

cysts are common.3. Roots tend to be thinner than normal.4. Secondary cementum is sparse or absent

on both dentitions.

Type-1(Classic Type)

-2(Perinatallethal)-3(Progressivelydeforming)

-4

AD,Blue sclera,Premature deafness,+/- DIAD

AD/AR.osteoporotic bone,progressivedeformity,DIAD,similar to Type 1 but

severe

This is clinical result ofmultiple supernumeraryteeth:retained deciduousdentition with delayed ornon eruption


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HistologicalFeatures

Thickened cortices.

Reduced marrow cavities.

Persistence of woven bone.

Marked lack of mature lamellar bone.

RadiographicalFeatures 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.

Here we can not seethe maxillary sinusesalthough they areexist.and we can notsee the roots ofteeth(see the belowpicture)

Chest X-ray for CD

This show the dentalabnormalities of thisdisease:multiplesupernumeraryteeth,thin roots,dentigerous cysts and

may be odontogenetictumors,secondarycementum is sparse orabsent in bothdentition.

The increaseddensity of boneoccurs in expenseof bone marrowthat leads to-2anemia-Neutropenia-Sth.aureusinfection-Osteomyelitis


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4.Fibro-osseus lesion a) Fibrous Dysplasia

A variety of disorders characterized by replacement ofnormal bone by cellular fibrousWhere?Woven bone and Acellular islands of mineralized tissuedevelop

Type 1. monostotic 2. polyostotic

IntroOne bone

(Any bone-most frequentlimbs,ribs,jaws> common(childhood+ adolescence)Maxilla > Mandible

Maxilla adjacent bone involved i.eZygoma + sphenoidterm used is craniofascial dys

Occasionally not diagnosed until adult life

-they may give history of recent expansion ofquiescent bony enlargement.-Reactivation is unknown,sllunya due topregnancy

> than one> than one2-3 times > in FVariable distributionBone in one of limb esp the lower- other skull,vertebrae,ribs,and pelvi-Almost any combination can occur ,theres

tendency for segmental + localization in 1limb/1 side of body

Severe cases diagnosed in childhood b/c ofassociated

Bony deformities

pathological fractures

Osseus dysplasia Benign Neoplasma)Fibrous Dysplasia(Dys)

1. -monostot ic2. -polyostotic

b)Cemento-osseous Dys

Periapical cemental Dys,Focal cemento-osseousDys,gigantiform dys

Ossifying Fibroma/

cemento-ossifyingfibroma

Etiology Developmental defect caused by mutation in GNAS1 gene in fetal (poly)+ postnatal(mono)

Fibrous Dysplasia

Clinical

Features

Increasing,painless swelling causing facialasymmetry

Smooth,fusiform,pronounced > bucallyMaxilla

- prominence of the cheek andbuccal expansion distal tocanine,which may extend totuberosity

- involve sinus,zygomaticprocess,orbital floor

- causes exophtalmus + proptosisMandibular

- Involve M + PM area- obvious protuberance + increase

depth of jaw

Both(either 1)- Displacement- Failure of teeth eruption

Canine fossa obliterated

May present as part ofMcCune-Albright syndrome:

- Rare & Severe- Caf-au-lait melanotic

spots on skin.- Precocious puberty in

females.- Occasional ly other

endocrineabnormalities.

- Premature skeletalmaturation.

- Pigmentation of oralmucosa reported.

Occurs in males without precociouspuberty

Hystologically:o Replacement of normal bone by fibrous

tissue containing islands and trabeculaeof metaplastic bone.

o Appearances of jaw lesions are more

variable than in other bones.

o Fibrous tissue may be richly cellular and

show a whorled pattern, or may consistof thick, interlacing collagen bundles.

o Newly formed bony trabeculae are

delicate and irregular (likened toChinese characters).

o They consist of immature, coarse-

fibered woven bone.

o In jaw lesions, trabeculae may be

thicker and blunter than in long bones.

o Spherical areas of calcification

resembling cemetum may be present.

o Osteoblastic and osteoclastic activity

may be seen in relationship to sometrabeculae.


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o At the margins, lesional bone fuses with

normal bone and this particular featuresdistinguishes FD from ossifying fibroma.

o

o Usually with increasing age, the amount

and cellularity of fibrous tissuedecreases and the amount of boneincreases.as the lesion matures, thereis progressive remodelling of wovenbone to lamellar bone.

o Occasionally, the lesion may be

associated with development ofaneurysmal bone cyst.

Lt: Histologically,it shows immature coarse fibered wovenbone(the pink parts of the right section)

With further remodeling ;lamellar bone may appears

Rt: notice the fibrous tissue(white with black dots)and wovenbone(dark pink)Usually with age the cellularity components decrease and thebone increases.

RadiographicalFeatures

1. Jaw lesions are variable in appearance,reflecting differing amounts of metaplasticbone formed within fibrous tissue.

2. Borders are difficult to define because ofgradual transition to normal.

3. Initially resemble cyst-like radiolucenciescontaining faint bony trabeculae.

4. With increasing trabeculation, theybecome mottled and eventually opaque.

5. The many delicate trabeculae give aground-glass or orange-peel-stipplingeffect.

6. In some lesions, coarse mottling ofsmoke-screen pattern produced byirregular radiopaque masses lying in aradiolucent background.

7. In the maxilla, lesions may extend up to

and distort, but do not cross suture lines.

8. Roots of teeth in involved areas may beseparated and teeth may be displaced,but root resorption is exceptional.

5. Achondroplasia

Behavior of Fibrous Dys. Of bone

Malignant trans.Fibrosarcoma

Some of cases followed radiotx.

Treated by conservative surgicalremoval to reduce deformity only

The lesion tend to expand mainlyduring the period of active skeletalgrowth + become quiescent in adultlife.

In jaws lesion there are variable appearances ofradiopaqe and radiolucent areas,depending onamount of metablastic deposited bone

spherical ofcalcificationresemblingcementum


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1. AD,sometimes due to spontaneous2. mutations3. Most common-Dwarfism4. Abnormality of endochondral

ossification5. Absent /defective zone of provisional

calcification of cartilage in epiphysesand base of skull

Clinical Features-Trunk & head of normal size - Limbs- short

-Middle pt of face-retrusive due to defective of skull base-Severe malocclusion

b)Cemento-osseous Dysplasia 6.Cherubism

Intro Term used to identify osseous dysplasiawhich localized to the jaws.> in female(> 30 yr)> in mandible

A rare disorder of bone,inherited in AD with varieties.

Name relates to clinical appearances & facial deformity cherubs(A representation of a small angel, portrayed as a child with a chubby rosy face)

Etiology Mutation in gene associated with fibroblast growth factor rec. 3(FGFR3)

Clinically Diff clinical presentations of the samedisordersA range of appearances :

1. Periapical cemental dys.- Multiple small lesions- Apical area of mand.incicors

2. Florid cemento-osseous dys.- Multiple large lesions- 1 or > quadrants in 1 or both jaws.

1. Painless bilateral swellings of the jaws appear bw 2- 4 yrs2. Swellings-symmetrical + involve mand/+ max

3. Enlarge rapidly to age 7 static regress

4. Progressive reduction in deformity as the patient passes from puberty into adult life.5. Cosmetic surgery is often needed to deal with residual deformity.6. Facial deformity : fullness of cheeks + jaws results in chubby face7. Theres rim of a sclera beneath the iris due to stretching of ski over swellings(cherubs appearance)8. Reactive hyperplasia of Submandibular LN adds to facial fullness9. Dental abnormalities:

- Premature loss of 1 teeth + displacement- Lack of eruption- Failure of development of 2 teeth

Histologically Features of fibro-osseous lesion.Fig16.13 m/s245

Cellular and vascular fibrous tissue containing varying amounts of multinucleated giant cells.

The appearance is similar to other giant cell lesions of the jaws, and differentiation between them

requires clinical and radiographic information.

As the activity of the lesion decreases, it becomes more fibrous, giant cell number diminishes,metaplastic bone is deposited.

Radiographyca

lly

Reflect the extent of mineralization

May be radiolucent,mixed,radiopaque

-Sharply defined, multilocular radiolucencies.

There are cellular and vascular fibrouscomponents.with varying amounts ofmultinucleated giant cells.

With time the fibrous components increases andthe giant cells decrease,and there is deposition ofmetablastic bone

notice the non-definedborder between which isnormal and abnormal.

gradual transition betweennormal and abnormal bone.The abnormal bone showsthe appearance of which iscalled ground glass\orange

peel stippling.


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There are poorly demarcatedRadiopaque areas that representing calcifiedtissue

-Expansion and thinning of cortical plates, even perforation.

-Mandibular lesions appear to begin near the angle and spread to involve the body and ramus.

-Maxillary lesions are often confined to tuberosities, but sinus may be obliterated.

DISORDERS OF BONE

Inherited and Developmental Disorders of Bone

1. Osteogenesis Imperfecta2. Osteopetrosis(Marble Bone Disease)3. Cleidocranial Dysplasia(Cleidocranial dysostosis)4. Achondroplasia

5. Fibro-OsseousLesions6. Fibrous Dysplasia of Bone7. Cemento-Osseous Dysplasia8. Cherubism

Healing of Bone

1. Healing of an extraction socket2. Osseointegrated implants

Inflammatory Disease of Bone

1. Alveolar Osteitis(Dry Socket)2. Focal Sclerosing(condensing) osteitis3. Osteomyelitis4. Chronic periostitis associated with5. hyaline bodies(pulse/vegetable granuloma)6. Radiation injury and osteoradionecrosis

Metabolic and Endocrine Disorders of Bone1. Osteoporosis2. Primary Hyperparathyroidism

3. Secondary Hyperparathyroidism4. Rickets & Osteomalacia5. Acromegaly

Pagets Disease of Bone

Central Giant Cell Granuloma

Torus Palatinus,Torus Mandibularis,and other Exostoses

Dense Bone Islands

Tumours of Bone1. Osteoma and Osteoblastoma2. Osteosacroma3. Chondroma and Chondrosarcoma4. Myeloma

5. Ossifying(cemento-ossifying) fibroma

Multilocularradiolucencies ,thinningof cortical bone (even

perforation),be aware

Confined lesions inthe maxilla to

tuberosities with

possibility of sinus


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Langerhans Cell HistiocytosisHaemangioma of Bone

Metastatic Tumours

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Inherited & Developmental Disorders