Non-inflammatory diseases of bone CLASS.pdf

Dr. Arun Mohan
Dept. of Oral and MaxillofacialPathology

Introduction
 Bone is a living tissue, which makes up the body
skeleton and is one of the hardest structures of the
animal body.
 It provides
 Shape and support for the body.
 Site of attachment for tendons and muscles, which are
essential for locomotion.
 Protection to vital organs in the body.
 Site for development and storage for blood cells.

CLASSIFICATION OF BONE
Bone
SHAPES
Eg: long, short, irregular, flat, sesamoid.
DEVELOPMENTALLY
Eg: endochondral, intramembranous.
HISTOLOGICALLY
Eg: mature, immature

Alveolar
bone
Alveolar
bone proper
Lamellated
bone
Bundle bone
Supporting
alveolar
bone
Spongy
bone
Cortical
plates

ALVEOLAR BONE PROPER
A) BUNDLE BONE
 Bundle bone is the part of alveolar bone, into
which the fiber bundles of the PDL insert.
 It is characterized by scarcity of fibrils in
intercellular substance.
 Fibrils arranged at right angles are
Sharpey’s Fibers
 Bundle bone is formed in areas of recent
bone deposition.
 Lines of rest seen in bundle bone.
 Radiographically it is called as Lamina
Dura because of increased radiopacity which
is due to the presence of thick bone without
trabeculations.
DENTIN
CEMENTUM
PDL
BUNDLE
BONE

The lamina dura (arrows) appears as a thin opaque layer of bone around
teeth, A, and around a recent extraction socket, B.
RADIOGRAPHICALLY

B) LAMELLATED BONE:
 It is the outer most part of
the alveolar bone proper.
 Some lamellae of the
lamellated bone are
arranged roughly parallel to
the surface of the adjacent
marrow spaces, whereas
others forms haversian
system.

SUPPORTING ALVEOLAR BONE
 It consists of two parts –
 Cortical plates (Outer and inner)
 Spongy bone
Cortical plates: these are made up
of compact bone & form the outer
and inner plates of alveolar bone.
Cortical bone varies in thickness in
different areas – it is thicker in
the mandible than in the maxilla
and thicker in the premolar-
molar region than in the anterior.

 Spongy bone: it fills the area between
the cortical plates and the alveolar
bone proper.
 It contains trabaculae of bone and
marrow spaces.
 Types of spongy bone (spongiosa) :-
 Type I: the trabaculae are regular
and horizontal like a ladder. This
is seen most commonly in the
mandible.
 Type II: irregularly arranged
delicate and numerous trabaculae.
This is seen most commonly in the
maxilla.
The spongy bone is very thin or absent
in the anterior regions of both the
jaws.

A. DEVELOPMENTAL DISEASES:
- Cheurbism
- Osteopetrosis
- Osteogenesis imperfecta
- Cleiodocrainal dysplasia
B. ENDOCRINAL DISEASES:
- Hyperparathyroidism
C. IDIOPATHIC DISEASES:
- Idiopathic osteosclerosis
- Massive osteolysis
- Langerhan’s cell disease (Histiocytosis-X)
- Paget’s disease

D. REACTIVE DISEASES:
- Giant cell lesion of bone
- Aneurysmal bone cyst
- Simple / Traumatic bone cyst
E. FIBRO-OSSEOUS LESIONS:
(i) Non-neoplastic lesions -
- Fibrous dysplasia
- Cemento-osseous dysplasia
(ii) Neoplasms –
- Ossifying fibroma

F. INFLAMMATORY DISEASES: -
(i) Specific:
- Tuberculosis
- Actinomycosis
(ii) Non specific
- Osteomyelitis
- Dry socket
- Periapical cyst / abscess / granuloma
- Osteoradionecrosis

G. NEOPLASTIC DISEASES: -
(i) Benign:
- Osteoma
- Osteoid osteoma & osteoblastoma
- Chondroma
- Chondromyxoid fibroma
(ii) Malignant:
- Osteosarcoma
- Ewing’s sarcoma
- Chondrosarcoma

Fibro-osseous lesions
I. Bone dysplasias
a. Fibrous dysplasia
i. Monostotic
ii. Polyostotic
iii. Polyostotic with endocrinopathy
(McCune-Albright)
iv. Osteofibrous dysplasia
b. Osteitis deformans
c. Pagetoid heritable bone
dysplasias of childhood
d. Segmental odontomaxillary
dysplasia
II. Cemento-osseous dysplasias
a. Focal cemento-osseous dysplasia
b. Florid cemento-osseous dysplasia
III. Inflammatory/reactive processes
a. Focal sclerosing osteomyelitis
b. Diffuse sclerosing osteomyelitis
c. Proliferative periostitis
IV. Metabolic Disease:
Hyperparathyroidism
V. Neoplastic lesions (Ossifying
fibromas)
a. Ossifying fibroma NOS
b. Hyperparathyroidism jaw lesion
syndrome
c. Juvenile ossifying fibroma
i. Trabecular type
ii. Psammomatoid type
d. Gigantiform cementomas

FIBROUS DYSPLASIA
 Condition in which normal medullary bone is gradually
replaced by an abnormal fibrous connective tissue
proliferation
 This mesenchymal tissue contains varying amounts of
osteoid that presumably arises through metaplasia.
 Due to a defect in osteoblast differentiation and
maturation

ETIOLOGY: -
1. Hamartomatous
2. Abnormal reaction of bone to a localized traumatic
episode
3. Mutation of GNAS1 gene – which codes for a G protein
which stimulates cAMP production. This leads to :-
- effect on differentiation of osteoblasts
- hyperfunction of affected endocrine glands
- increased prolifearation of melanocytes

TYPES OF FIBROUS DYSPLASIA: -
1. Monostotic: Fibrous dysplasia (FD) limited to one
single bone. Accounts for 70% – 80% of all cases
2. Polyostotic: FD affects several bones. 20-30% cases
(a) Jaffe type – severe FD with almost entire
skeleton involved.
(b) McCune-Albright syndrome – along with
polyostotic FD, multiple cutaneous pigmentations
and hyperfunction of one or more endocrine glands.

3. Craniofacial form
4. Cherubism

MONOSTOTIC FIBROUS DYSPLASIA
Clinical Features : -
Age incidence: 1st or 2nd decade of life.
Sex incidence: equal
Site predilection:
 Ribs, tibia, femur, craniofacial bones
 Maxilla involved more than mandible.
 Maxillary lesions often involve adjacent bones like
zygoma, sphenoid etc

Signs & symptoms:
 First clinical sign is a painless,
gradually enlarging swelling
 Usually involves buccal cortical plate
 Causes protuberance of inferior border
of mandible
 Teeth may be displaced by the mass
 Maxillary lesions – more complications

POLYOSTOTIC FIBROUS DYSPLASIA
Clinical Features : -
Age incidence: 1st decade of life, earlier
Sex incidence: Equal
Site predilection: Skull and facial bones, pelvis, spine
and shoulder girdle

Signs & symptoms: -
 Pathological fractures, other bone
symptoms
 Patients with McCune-Albright
syndrome have café-au-lait (coffee
with milk) pigmentation.
 Typically, margins of the spots are
irregular, unlike those of
neurofibromatosis, where the spots
have smooth borders
( Also occurs ipsilateral to the side of
bone involvement )

Coast of Maine –
Irregular borders –
McCune Albright
syndrome
Coast of California –
Smooth borders –
Neurofibramatosis

 Hyperthyroidism
 Acromegaly
 Precocious puberty
 Hyperparathyroidism
 Hypophosphatemic rickets
 Severe cases – hepatic (increased hepatic transaminases)
- cardiac (cardiomyopathy)
- GI polyposis
 Mazabraud’s syndrome – association b/w FD and
intramuscular myxoma

RADIOGRAPHIC FEATURES: -
 Early stages – mixed radiopaque-
radiolucent appearance.
(well-defined radiolucency containing
network of fine bony trabaculae)
 Later stages show a characteristic
“ground glass / orange peel (peau d’
orange)” appearance of affected bones.
- opaque with many delicate trabaculae

 Lesions not well defined and blend into adjacent bone –
limits of lesion cannot be defined.
 Lesions in jaws displace roots of teeth
 Distortion of nasal cavity and obliteration of paranasal
sinuses
 Rind sign – lucent lesions with sclerotic borders

HISTOLOGICAL FEATURES: -
 Lesion shows typical irregularly
shaped trabeculae of immature
woven bone in a cellular, loosely
arranged fibrous stroma
 Theses trabeculae are not
connected to each other
 They often assume curvilinear
shape, which have been linked to
Chinese script writing or
Cuneiform pattern

 These trabeculae are believed to arise due to
metaplasia and are not bordered by plump,
functional osteoblasts
 The surrounding stroma is highly cellular and
vascular
 Tiny calcified spherules maybe seen in some areas
 Lesional bone fuses directly with normal bone at the
periphery, no demarcation

Irregular trabaculae of woven bone in a fibrous matrix

 Long standing lesions of jaws and skull, esp in old
patients, tend to be more ossified
 May show lamellar deposition of trabculae
 Not seen in long bones

DIFFERENTIAL DIAGNOSIS: -
 Clinically, FD must be differentiated from
1. Ossifying fibroma
2. Paget’s disease.
 Though, its radiographic appearance is typical, it must
be distinguished from
1. Hyperparathyroidism.
2. Paget’s disease (early stage).

CHERUBISM
Rare developmental jaw condition, first
described by Jones in 1933.
- called it familial multilocular disease
of the jaw.
Transmitted as an autosomal dominant
trait.

 Causes characteristic bilateral posterior
mandibular swelling
- the child appears as a plump cheeked angels
called “Cherub” in Renaissance paintings.

Pathogenesis
 The gene for cherubism was mapped to chromosome
4p16 ( SH3BP2 gene )
 The protein encoded by this gene is believed to function in
signal transduction pathway and to increase the activity of
osteoclasts and osteoblasts during growth phase
 It has been suggested that mutation in SH3BP2 gene may
lead to pathologic activation of osteoclasts and disruption
of jaw morphogenesis

 The appearance of people with the disorder is
caused by a loss of bone, which the body replaces
with excessive amounts of fibrous tissue.

CLINICAL FEATURES: -
Age incidence: Affected children, are normal at the birth and
are without any clinically or radiographically evident disease
until 14 months to 3 yrs of age
The jaw lesion remit spontaneously when the child reaches
puberty, but reason for this remission is still unknown.
Sex incidence: males = females

Site predilection:
 Mostly bilateral involvement
 Painless and symmetrical expansion
 Mandible affected more commonly than maxilla
 In maxilla, tuberosity region is affected frequently
- resulting in respiratory obstruction and
impairment of vision & hearing
 Cervical lymphadenopathy contributes to the
patients full faced appearance

 Skin of upper face is stretched
 A rim of sclera may be seen beneath the
iris, giving a classical “eyes upturned
to heaven” appearance
- due to involvement of the
infraorbital rim and orbital floor that
tilts the eyeball upwards, as well as to
stretching of the facial skin that pulls
the lower lid downwards.

 Developing teeth displaced, fail to
erupt.
 Numerous dental abnormalities have been
reported, such as agenesis of the 2nd & 3rd
mandibular molars, premature exfoliation of
the primary teeth, delayed eruption of the
permanent teeth, displacement of the teeth
and transposition and rotation of the teeth.
 The permanent dentition is often defective.
 In severe cases root resorption occurs.

 It is been connected to NOONAN’S SYNDROME
- short stature, cherubic facies, congenital heart defect,
chest deformity, low I.Q.
 Grading system, Arnott (1978)
Grade I: involvement both ascending rami of mandible
Grade II: involvement both maxillary tuberosities as well as
both ascending rami of mandible
Grade III: involvement of the whole maxilla and mandible
except the coronoid process and condyles

RADIOGRAPHIC FEATURES
 Appear as expansile, multilocular
radiolucency.
 The presence of numerous unerupted
teeth and the destruction of the
alveolar bone may displace the teeth,
producing a radiographic appearance
referred as floating tooth syndrome.
 With adulthood, the cystic areas in the
jaws become re-ossified, which results
in irregular patchy sclerosis.
 There is classic but non specific
ground glass appearance because of
the small, tightly compressed
trabecular pattern.

HISTOLOGICAL FEATURES
 Normal bone is partly replaced by
pathologic tissue
 Numerous randomly distributed
multinucleated giant cells and
vascular spaces within a fibrous
connective tissue stroma
 An increase in osteoid and newly
formed bone matrix is found in the
peripheral region
 An eosinophilic perivascular cuffing
is seen

Multinucleated giant cells are scattered
in vascular fibrous stroma. Osteoid and
newly formed bone matrix are visible
Multinucleated giant cells are
scattered around blood vessels

Multinucleated giant cells in cherubism are
positive for tartrate resistant acid
phosphatase (TRAP)

DIFFERENTIAL DIAGNOSIS
 Giant cell granulomas of the jaw
 Osteoclastomas
 Aneurysmal bone cyst
 Fibrous dysplasia
 Hyperparathyroidism

TREATMENT
 It is based on the known natural course of the disease
and the clinical behaviour of the individual case.
 If necessary surgery is undertaken only after puberty.

PAGET’S DISEASE OF BONE
(Osteitis deformans)
 Characterized by excessive and abnormal remodelling of
bone, resulting in distortion and weakening of bone.
 Sir James Paget
 Pagetic bone - extensively vascularized, weak, enlarged
and deformed with subsequent complications.

ETIOLOGY: -
 Unknown, but predisposing factors could be –
Genetic – 7 to 10 fold increase in relatives
Slow virus infection – inclusion bodies in Pagetic osteoclasts
Inflammatory - response to NSAIDs
Endocrine factors – PTH levels

CLINICAL FEATURES
Age incidence: Middle aged individuals
Sex incidence: Male to female ratio is 2:1
Site predilection: Bones of skull, lumbar vertebrae,
pelvis, femur and tibia
Common in England, France and Germany.
Rare in Middle and Far East Asia and Africa.

 Severe bone pain and limitation of
joint movements
- dull, constant aching pain ,may exacerbate
at night
 Pathologic fractures
 Affected bones – thickened, enlarged and
weak
 Weight bearing joints/bones become
bowed – Simian stance
 Rise in temperature on the skin overlying
involved bone

 Skull involvement – increase in head circumference
 Platybasia – softened bone at base of skull
– descend of cranium into cervical spine
 Non-specific head aches, dizziness, dementia, tinnitus,
impaired hearing, changes in vision, cranial nerve
palsies
 Back and neck pain – affects spine

 Maxilla affected more than mandible
 Maxilla – enlargement of middle third
of face (leontiasis ossea)
 Nasal obstruction, obliterated sinuses
and deviated septum also occur
 Mandible involved rarely – may cause
prognathism
 In dentulous patients spacing of teeth
is seen, while edentulous patients
complains of tightness of the dentures

RADIOGRAPHIC FEATURES
 Early stage (osteolytic) -
radiolucency and alteration of
trabecular pattern
Isolated areas (osteoporosis
circumscripta)-diffuse areas
 Late stage (osteoblastic) – patchy
areas of sclerotic bone is formed,
called “cotton wool” appearance

 Dental radiographs also
show the classical cotton
wool appearance
 Extensive hypercementosis
can be noted

DIFFERENTIAL DIAGNOSIS: -
 Acromegaly.
 Florid cemento- osseous dysplasia.
 Sclerosing osteomyelitis (diffuse type).
 Osteosarcoma.
 Adult osteopetrosis

LABORATORYFINDINGS: -
 Abnormally elevated serum alkaline
phosphatase level upto 250 Bodansky units
(normal – 30 to 40);
but normal calcium and phosphorous levels.
 Increased urinary calcium and hydroxyproline
levels.

HISTOLOGICAL FEATURES
 Alternating bone resorption and
deposition seen
 Depends on stage of the disease
1) Osteolytic phase
 Disordered areas of resorption
 Increased number of abnormally
large osteoclasts
(upto 100 nuclei)

2) Osteoblastic phase
 Haphazard laying of new
bone matrix (woven bone)
 Repeated bone removal &
deposition – formation of
many small irregularly shaped
bone fragments – joined
together in jigsaw or mosaic
pattern (hallmark H/P
feature)
 Basophilic reversal lines
 High vascularity, increased
number of capillaries, dilated
arterioles and venous sinuses

 Pagetic bone is coarse and fibrous with distortion of
normal trabecular arrangement
 Shows no tendancy to form Haversian systems or to
center on blood vessels
3) Osteoporotic phase
 Burned-out phase
 New bone is disordered, poorly mineralized and lacks
structural integrity
 Proliferation of bone and concomitant
hypercementosis may result in obliteration of PDL

Treatment
 It is a chronic and slow growing diease, it is seldom the
cause of death.
 Bone pain is mostly controlled by anti-inflammatory
drugs.

OSTEOGENESIS IMPERFECTA
 Most common type of developmental bone disorder,
showing both autosomal dominant and recessive pattern.
 Comprises heterogeneous group of heritable CT disorder in
which bone fragility is the primary feature.
 Synonyms- Brittle bone disease
- Fragilitas ossium
- Osteopsathyrosis
- Lobstein’s disease

 Etiology
 Impairment of collagen maturation.
 Also- Mutations in one of the 2 genes that guide the formation of
Type I collagen: the COL1A1 gene on chromosome 17 and the
COL1A2 gene on chromosome 7.
 Type I collagen forms a major portion of bone, dentine, sclerae,
ligaments, and dermis of skin; OI demonstrates a variety of
changes that involves these sites.
66

CLINICAL FEATURES
 The chief clinical feature is the extreme fragility and porosity
of the bones, with an increased proneness to fracture.
 Upon fracture, healing will occur but may be associated with
exuberant callus formation – the new bone formed will be of
same quality
 Abnormal collagenous maturation results in bone with thin
cortex, fine trabeculation, and diffused osteoporosis.

 The other
characteristic feature
of OI is the
occurrence of
blue sclera.
 The sclera is
abnormally thin, and
for this reason the
pigmented choroid
shows through and
produces the bluish
colour.

Other conditions in which blue
sclera can be seen
 Osteopetrosis
 Fetal rickets
 Turner syndrome
 Pagets disease
 Marfan syndrome
 Ehlers-Danlos syndrome.

 Deafness- due to osteosclerosis.
 Tendency towards capillary bleeding.

 Four types present, each having several subtypes :-
TYPE I Osteogenesis imperfecta:
 Commonest type – autosomal dominant.
 Mild to moderate bone fragility – onset is highly variable
– may be present at birth also.
 Hearing loss develops before 30 years.
 Blue sclera is seen.
 Kyphoscoliosis
 Short stature
 Some patients may show opalescent dentin

Deformity of long bones
Opalescent dentin

TYPE II Osteogenesis
imperfecta:
 Extreme bone fragility with
frequent fractures.
 Most lethal
- many patients stillborn
– 90% die before 4 weeks of age
 Blue sclera, hearing loss
 Micrognathia
 Short trunk.

TYPE III Osteogenesis imperfecta:
 Moderate to severe bone fragility
 Blue sclera present in infants but fades by
adulthood
 Mortality rate higher in older children
 Death from cardiopulmonary
complications caused by kyphoscoliosis
 Opalescent dentin
 Triangluar face, with frontal bossing
 Short limbs

TYPE IV Osteogenesis imperfecta: -
 Mild to moderate bone fragility
 Sclera pale in early life, but fades in later life
 Fractures present in 50 % case – frequency of fractures
decreases after puberty
 Some patients may have opalescent dentin

Oral manifestation:
• Both the dentitions are affected, and demonstrate grey to
brown translucency.
• Although the altered teeth closely resemble
dentinogenesis imperfecta , the two disease are the result
of different mutations and should be considered as
separate processes.

• Class III malocclusion; due to maxillary hypoplasia
rather than mandibular hyperplasia.
• Anterior and posterior cross bite and open bites can
be seen.
• Large numbers of impacted and ectopic teeth can be
reported
- Unerupted 1st and 2nd molar is very
common feature.

Regezi, Sciubba: Oral pathology. 4th edition
79
Amber brown to grey translucent teeth

 Radiologicalfeatures
 Osteopenia, bowing, angulation or deformity of the long bones, multiple
fractures
 Intraoral radiographs typically reveal premature pulp obliteration, along with
shell teeth.
80
Regezi, Sciubba: Oral pathology. 4th edition
Obliterated pulp chamber

 Mass of cortical and cancellous bone is
abnormal and greatly reduced
 Osteoblasts are present but bone matrix
synthesis is reduced
 Bone architecture remains immature
throughout life
 There is a failure of woven bone to
become transformed to lamellar bone

Treatment
 No known treatment.
 Only treatment of the infection when they occur.

CLEIDOCRANIAL DYSPLASIA
 Bone defects primarily involve skull and clavicle – defects seen in
other bone also
 Inherited as autosomal dominant trait, but almost 40% cases show
spontaneous mutation
 It is caused due to defect in CBFA 1 gene also called as RUNX 2 gene
of chromosome 6p21 ( a key transcription factor associated with osteoblast
differentiation)

Age incidence: Children
Sex incidence: Nil
Site predilection: Skull, clavicles and jaw bones.

 Patients show unusual mobility of
shoulders due to absence /
hypoplasia of clavicles.
 Shoulders narrow and droop
excessively.
 Short height with large heads
showing pronounced frontal,
occipital and parietal bossing.

 Nose is broad with depressed nasal bridge
- Ocular hypertelorism
 Sagittal suture is sunken giving the skull a flat
appearance.
 Paranasal sinuses are under developed

Oral manifestations:
 Narrow, high arched palate.
 Increased prevalence of cleft
palate.
 Maxilla is underdeveloped and
smaller than mandible.
 Prolonged retention of deciduous
teeth and delay / complete failure
of eruption of permanent teeth
- multiple unerupted teeth

Radiographic
features
 OPG and dental
radiographs show
multiple impacted and
supernumerary teeth.
 Downward curvature of
zygomatic arch
 Underdeveloped maxilla,
very small or absent
sinuses
 Hypoplastic nasal bones

Treatment
 No treatment exists for the skull, clavicular, and other
bone anomalies associated with CCD.
 Most patient function well with out any significant
problem.

 Synonyms- Marfan- Achard syndrome, arachnodactly
 Heritable genetic defect of connective tissue that has an autosomal
dominant transmission.
 Etiology
 Defect itself has been isolated to FBN1 gene on chromosome 15,
which codes for connective tissue protein fibrillin.
 Abnormalities in this protein cause a myriad of distinct clinical
problems of which the musculoskeletal, cardiac & ocular
problems predominate.
92
Marfan syndrome

 Dolichostenomelia
 Arachynodactyly
 Shape of skull and face is characteristically long and
narrow
 Kyphosis & Scoliosis, pectorus excavatum
 Flat foot
 Myopia & Bilateral ectopialentis
CLINICAL FEATURES

Steinberg sign Walker – Murdoch
sign

• Aortic aneurysm and
regurgitation.
• Valvular defects.
• Enlargement of
heart.
Cardiovascular
complications

Oral Manifestations
 Narrow & high-arched palate .
 Dental crowding.
 Bifid uvula is also reported.
 Multiple odontogenic cysts of jaws have been reported.
Radiological features
 Skull radiographs may demonstrate
a high arched palate, increased skull height
& enlarged frontal sinus.
99

Complications
 Dislocations
 Cardiovascular complications
 Ocular complications
Treatment
 Morbidity and mortality are directly related to the degree of
connective tissue abnormality in the involved organ systems.
 Annual medical examination with a cardiovascular
emphasis, frequent ophthalmologic examination.
100

DOWN SYNDROME
 Trisomy 21, Mongolism
 Nearly half of the fetuses abort during early pregnancy
 Increased maternal age (esp above 45 years)
 Parents with one affected child – high risk of
recurrence

Etiology :-
 Trisomy 21 (95% cases) – 47 chromosomes
- non-disjunction
 Chromosomal translocation (mostly 21 22)
 Chromosomal mosaicism

Clinical Features :-
 Low I.Q - 25-50
 Brachycephaly
 Flat facies
Depressed nasal bridge
Hypertelorism
 Flat occiput
 Broad short neck
 Delayed and incomplete
puberty
 Protuberant abdomen

Skeletal abnormalities
 Short stature
 Broad and short hands, feet and digit
 Wide gap between 1st and 2nd toes
 Short curved fifth fingers - Clinodactyly
 Joint laxity

 Narrow, upward and
outward slanting of the
palpebral fissures
 Medial epicanthal fold
 Strabismus
 Cataract – early age
 Retinal detachment

Oral Manifestations:-
 Small mouth
Protuberant tongue
(Macroglossia)
 Fissured tongue
 Fissuring and
thickening of lips
Cleft lip and palate
 Angular chelitis
High arched palate with decreased
width and length

ACHONDROPLASIA
 Achondroplasia is caused by mutations in the gene
for fibroblast growth factor receptor-3 (FGFR3).
 Autosomal dominant trait; but 80% de novo
 Caused by disturbance in cartilage mediated
(endochondral) ossification
 Most common form of dwarfism in humans

 Short stature
 Normal trunk length, disproportionately short limbs
 Trident hands
 Large calvarial bones in contrast to the small cranial base and
facial bones
 Thoracolumbar gibbus in infancy, which usually disappears with
walking
 Frontal bossing, hypoplasia of midface, malocclusion
 Normal intelligence, sometimes endowed with abnormal strength
and agility

LANGERHANS CELL DISEASE (Histiocytosis X)
 It is an idiopathic disease characterized by proliferation
of histiocyte like cells (Langerhan's cells), that are
accompanied by varying numbers of eosinophils,
lymphocytes, plasma cells & multinucleated giant cells

TYPES: -
1. Eosinophilic granuloma of bone:
Solitary / multiple bone involvement without systemic organ
involvement. It causes localized bone destruction with swelling
and often pain
2. Hand-Schüller-Christian disease:
Chronic disseminated disease involving bones, viscera and skin. It
shows triad of lytic skull lesion, exophthalmous, and diabetes
insipidus
3. Letterer-Siwe disease:
Acute disseminated disease with bone, visceral and skin
involvement, occurring mainly in infants

Age incidence: Predominantly children
below 10 years of age.
Sex incidence: Definite male predilection.
Site predilection:
 Bones - Skull, ribs, vertebrae, femur and mandible
most frequently.
 Oral – Gingiva and lips most commonly.

Signs & symptoms:
 Involved bones manifest dull pain and tenderness.
- Usually associated with an overlying
soft tissue lesion
 Visceral involvement results in failure of affected
organ.

 Jaw bone involvement
results in loosening of teeth
which resembles aggressive
periodontitis, and the
appearance of teeth
“floating in air” are typical
 Oral mucosa may show
ulcerative / proliferative
masses on gingiva

RADIOGRAPHIC
FEATURES: -
 Multiple, well / poorly defined
punched out radiolucent
areas seen.
 Extensive alveolar bone loss
occurs, causing the teeth to
appear as if they are “floating
in air”.

 Lesion shows diffuse infiltration of
pale staining, mononuclear cells
containing ill defined cell borders
and vesicular nuclei.
 Darker staining eosinophils, plasma
cells and lymphocytes and
multinucleated giant cells also seen.
 Electron microscopy shows rod /
racquet shaped characteristic
Birbeck granules(HX bodies)
within cytoplasm of Langerhan's
cells.
Birbeck granules, also known as Birbeck bodies, are rod shaped or "tennis-
racket" cytoplasmic organelles with a central linear density and a striated
appearance.

• Immunohistochemical
studies are needed to
confirm the diagnosis as
these cells cannot be
distinguished from normal
histiocytes
• Langerhan’s cells stain
positively for S-100
protein and CD1a cell
surface antigen

Pierre Robin Syndrome
(Robin Sequence)
 Occurs as isolated
syndrome or as part of a
complex of multiple
congenital anomalies
 Described by French dental
surgeon Pierre Robin

Etiology :-
 Mechanical theory:-
Lack of amniotic fluid (Oligohydramnios)
cause mandibular hypoplasia
- tongue gets impacted b/w palatal shelves
 Neurological maturation theory:-
- delay in neurological maturation of tongue, palate,
pharyngeal muscles ;
and hypoglossal nerve conduction

Clinical Features :-
 Micrognathia / Retrognathia (92% cases)
- Small body, more obtuse gonial angle,
posteriorily placed condyles
- Resolves by 5-6 years of age
 Cleft palate –
U-shaped cleft palate with no cleft lip
 Glossoptosis – with airway obstruction
- sleep apnea

 Syndactyly
 Abnormal digits
 Clinodactyly
 Polydactyly
 Hyperextensible joints

OSTEOPETROSIS
(Albers - Schönberg Disease, Marble bone disease)
 Rare hereditary bone disorder characterized by
increase in bone density due to defect in bone
remodeling caused by failure of normal osteoclast
function
 Clinical types – infantile, intermidiate and adult
osteopetrosis

PATHOGENESIS: -
 Osteoclasts fail to function normally
 Defective bone resorption combined with continued
bone deposition results in thickening of cortical
bone and sclerosis of cancellous bone
 Exact pathogenesis unknown, though a deficiency
of carbonic anhydrase is noted in osteoclasts

Deficiency of carbonic anhydrase in osteoclasts
Defective H+ ion pumping by osteoclasts
Defective bone resorption by osteoclasts
(Acidic environment is needed)
Bone resorption fails, bone formation persists
Excessive bone is formed

I. Infantile osteopetrosis
 Autosomal recessive trait
 Diffusely sclerotic skeleton, marrow failure and signs
of cranial nerve compression present
 Initial signs – normocytic normochromic anemia
and hepatosplenomegaly, due to compensatory
extramedullary heamatopoiesis
 Granulocytopenia
- increased susceptibility to infections

III. Adult osteopetrosis
 Discovered late in life – milder symptoms.
 Autosomal dominant trait.
 About 40% cases are asymptomatic.
 Axial skeleton shows sclerosis, while long bones show
little or no defects.
 Bone pain maybe seen
 10% shows osteomyelitis of mandible
 Marrow failure and hepatosplenomegaly are rare

Oral and Maxillofacial manifestations:
 Hypertelorism
 Frontal bossing
 Delayed tooth eruption and osteomyelitis of jaws
 Sclerosis of skull bones leads to narrowing of foramina
which causes compression of various cranial nerves –
blindness, deafness, facial paralysis etc
 Fracture of jaws during extraction procedure can occur
without undue force, due to fragility of the bone

RADIOGRAPHIC FEATURES: -
• Wide spread increase in bone density.
• Distinction between cortical and cancellous bone is lost.
• Dental X rays – difficult to distinguish roots.
• thickening of skull bone – especially towards base
• Vertebrae becomes sclerotic - Rugger jersey bands

HISTOLOGICAL FEATURES:
 A failure of osteoclasts to resorb skeletal tissue,
with remnants of mineralized primary spongiosa
that persist as islands of calcified immature bone
within mature bone, is characteristic of
osteopetrosis
 Globular amorphous bone
deposition in marrow spaces

 The number of osteoclasts may be increased,
normal or decreased, but there is no evidence of
functional osteoclast as Howship’s lacunae are not
visible.

Non-inflammatory diseases of bone CLASS.pdf

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Non-inflammatory diseases of bone CLASS.pdf