Bone pathology Flashcards
What is spongy bone
- trabeculae
- contains bone marrow
- contains canaliculi
What are canaliculi
communication between adjacent cavities
What is compact bone
- osteons are functional units
- the central haversion canal is encased in lamella
What is the outermost layer of bone
periosteum
What are osteoclasts
remove bone
found in howship’s lacunae
What are osteoblasts
- facilitate mineralization of osteoid matrix
- interconnected via dendritix extensions
What are osteocytes
differnetiated osteoblasts
trapped in bone matrix
contain cytoplasmic projections with osteoblasts and osteocytes
What stimuli can impact bone deposition and resorption
- mechanical
- systemic
- cytokines
What systemic hormones impact bone resorption/deposition
- PTH
- vitamin d3
- oestrogen
- growth hormone
How does PTH impact bone remodelling
- secretion controlled by serum calcium
- reduced serum calcium results in increased PTH
- increased PTH increases bone resorption
How does oestrogen impact bone remodelling
- inhibits bone resorption
- this is why women are more prone to OP in menopause
What are examples of developmental bone abnormalities
- torus
- osteogenesis imperfecta
- achondroplasia
- osteopetrosis
- fibrous dysplasia
What is a torus
- exostosis
- torus palatinus = midline of palate
- torus mandibularis = in mandible
What is an exostosis
defined as an extra growth of bone that extends outward from existing bone
Where is tori mandibularis usually seen
- lingual aspect of mandible
- premolar region
- generally unproblematic unless px wants denture
What is osteogenesis imperfecta
- type 1 collagen defect
What are the 4 main types of osteogenesis imperfect
numbered 1-4
type 1 = most mild
type 2 = most severe
type 3 = dentally related
How do osteogenesis imperfecta px present clinically
weak bones
multiple fractures
sometimes associated with dentinogenesis imperfecta
What is achondroplasia
- autosomal dominant
- problem with long bone formation
- poor endochondral ossification
- no significant dental related problems
What is osteopetrosis
- lack of osteoclast activity
- failure of resorption
- leads to marrow obliteration
What is the dental significance of osteopetrosis
- difficult extractions
- delayed healing
What is fibrous dysplasia
- due to gene defect
- slow growing, asymptomatic bony swelling where bone is replaced by fibrous tissue
What age group do we see fibrous dysplasia
- active in under 20s
- usually stops growing after active growth period
- surgery should be delayed until after growth
What are the types of fibrous dysplasia
- monostotoic
- polyostotic
What is monostotic fibrous dysplasia
single bone effected
What is polyostotic fibrous dysplasia
many bones effected
How does monostotic fibrous dysplasia present
the more common one
more common in mandible
may present as asymmetry on one side
What is polyostotic fibrous dysplasia
- usually part of a syndrome
What syndrome is polyostotic fibrous dysplasia associated with
Albright’s syndrome
* also present with melanin spots
* girls can experience early puberty
How does fibrous dysplasia appear radiographically
- cotton wool appearance
- ill defined margins which blend into bone
- bone maintains approximate shape initially
- becomes more radiopaque as the lesion matures
What are the histological features of fibrous dysplasia
- fibro-osseous appearance
- fibrous replacement of bone with cellular fibrous tissue
- bone is metaplastic or woven but will remodel and increase in density
- no capsule, not seperated from adj bone
Why should other tests be done for fibrous dysplasia
- it can involve other bone conditions
- should do other tests to take them into account
What is rarefying osteitis
- localised loss of bone in response to inflammation
- it is a process, not a pathology
What causes rarefying osteitis
- inflammatory factors coming from necrotic pulp and resorb the apex
- if at the apex of the tooth, consider PA periodontitis, periapical granuloma or periapical abscess
What is sclerosising osteitis
- localised increase in bone density in response to low grade inflammation
- most common around apex of a tooth with a necrotic pulp
How does sclerosing osteitis present
- periapical radiopacity
- often poorly defined
- may eventually lead to external root resorption if chronic
*also known as condensing osteitis
What is idiopathic osteosclerosis
- localised increase in bone density of unknown cause
Where is idiopathic osteosclerosis most common
- premolar/molar region of mandible
How does idiopathic osteosclerosis present
- always asymptomatic
- no bony expansion
- no effect on adj structures
- similar to sclerosising osteitis - vitality test and look out for symptoms
What is alveolar osteitis aka
dry socket
complication of XLA
What is alveolar osteitis due to
clot being lost too early
should be recognised as part of healing process
leaves behind bony sequestra
How does alveolar osteitis present
sevrere pain
What are risk factors for alveolar osteitis
- smoking
- OCP
- difficult XLA
- mandible
- posterior
- rinsing too soon
What is the management of dry socket
- can use medicaments e.g alveogyl however can slow healing
- best management = encourage healing and allow new clot formation
What is osteomyelitis
rare endogenous infection
What is the theory surrounding the cause of osteomyelitis
- compound fracture creation when performing XLA which exposes the fracture to the air
- can be acute or chronic
*
What may osteomyelitis present with
- sequestreum
- actinomycosis
- chronic diffuse sclerosing osteomyelitis
- periostitis productive - inflammation of the periosteum
What are the 2 main types of osteomyelitis
supparitve
garre’s ostemyelitis - periostitis productive
What is supparative osteomyelitis
- source of infeciton = teeth e.g abscess
- anaerobic predominate
- mandible most ocmmon
- vascular supply reduced
- organisms proliferate in the marrow space - acute inflammatory reaction
- necrosis and suppuration ensue
- sequestreum may exfoliate or be removed surgically
What are the symptoms of acute osteomyelitis
fever
malaise
swelling
pain
trismus
What are symptoms of chronic osteomyelitis
swelling
pain
chronic suppuration
What is Garre’s ostemyelitis
- most common in children and adults
- periosteal osteosclerosis presenting clinically as a bony hard swelling on the outer surface of hte mandible
- periosteal reaction is thought to result from the spread of a low grade, chronic apical inflammation through the cortical bone
- xray will show overgrowth of bone
What are other causes of bony necrosis
avascular necrosis - reduction of blood supply
irradiation
What can avascular necrosis be further split into
age related ischaemia
antiresorptive medications
What are examples of metabolic bone diseases
- osteoporosis
- rickets and osteomalacia
- hyperparathyroidism
What is osteoporosis
bone loss > bone apposition
What are the greatest risk factors for osteoporosis
- sex hormone status - post menopausal women
- age - bone apposition reduces with age
- calcium status and physical activity
- secondary osteoporosis
What conditions result in secondary osteoporosis
cushing’s
primary hyperparathyroidism
thyrotoxosis
How does osteoporosis present
- usually symptomless until something bad happens
- weak bone (normal composition, reduced quantity)
- in edentulous px may only be thin strip of bone left
- antrum enlargred
How will osteoporsosis appear on xray
- normal trabeculae lost
- will appear as loss of bone markings
What is significant about the medications taken for osteoporosis
MRONJ risk
What is rickets and osteomalacia
- osteoid laid down but not fully calcified
What is the cause of osteomalacia/rickets
lack of vitamin d
usually due to
* diet
* lack of sunlight
* malabsorption
* renal causes
What may a px with rickets present with
- poor endochondral bone
- low calcium
- raised alkaline phosphatase
How does the body try to increase serum calcium
- increased calcium absorption into the gut
- increased calcium resorption in the kidney
- stimulate osteoclast activity
How does hyperparathyroidism present
- calcium mobilised from bone
- generalized osteoporosis
- osteitis fibrosa cystic - aka browns tumour
- metastatic calcification of the kidney due to increase calcium in the blood
What are the types of hyperthyroidism
- primary - neoplasio//hyperplasia
- secondary - hypocalcaemia e.g vitamin D deficiency
- tertiary - prolonged secondary results in hyperplasia
How does primary hyperthyroidism present
- usually due to parathyroid adenoma
- mainly post menopausal women
- blood tests will show hypercalcaemia and increased bone turnover
- 10% present with brown’s tumour
What is brown’s tumour
- focal area of bone resorption results in formation of lesions called browns tumour
- large number of multinucleate, osteoclast like giant cells are scattered in a highly cellular vascular fibroblastic connective tissue stroma
- hemosiderin pigment present
What is the radiographic appearance of primary hyperparathyroidism
- may show no detectable changes or a generalized osteoporosis
- partial loss of lamina dura
What is the radiographic appearance of browns tumour
- sharply defined round or oval radioluceny area
- may appear mutlilocular
- more common in mandible
What are the 2 types of giant cell lesions
peripheral giant cell epulis
central giant cell granuloma
How does peripheral giant cell epulis present
swelling on gingiva
may be a sole lesions
may be a central giant cell granuloma which bursts out of the bone and presents as a peripheral giant cell epulis
Which age group is central giant cell granuloma most common in
10-25 YO
most common in mandible
How does central giant cell granuloma present
- may be multilocular
- possible swelling of bone
- tends to grow along length of the jaw so often gets quite large before becoming apparent
- may thin, expand or perforate the cortex
- teeth may be displaced and their roots resorbed
How does a central giant cell granuloma appear histologically
- multinucleate osteoclast giant cells are present
What is the differential diagnosis for giant cell lesions
- browns tumour
- aneurysmal bone cyst
- giant cell tumour
What is cherubism
- rare condition
- autosomal dominant inheritance
How does cherubism present
- multicystic/multilocular lesions in multiple quadrants
- painless swelling
- lesions grow until 7 YO then regress
- histologically: vascular giant cell lesion
What age group and gender does Paget’s disease effect
> 40 YO
M>F
What is the aetiology of Pagets
- racial deposition - more common in British Migrants e.g AUS
- viral - measles?
- no real known cause atm
What is monostotic paget’s
one bone involved
What is polystotic paget’s
> 1 bone involved
What will blood tests for paget’s show
raised alkaline phosphotase
What will paget’s present with
- bony swelling - look for changes in facial profile and oclcusion
- pain
- nerve compression
- motor and sensory disturbance if skull involved
How does Paget’s present radiographically
variable bone pattern
* changes as disease progresses
* osteoporotic/mixed/osteosclerotic
* can have cotton wool appearance
Dental changes
* loss of lamina dura
* hypercementosis
* migration
What is the histology of Paget’s
- increased bone turnover
- osteoblastic and osteoclastic activity next to each other
- disorganized remodelling results in bony trabeculae showing numerous criss-crossing, resting and scalloped reversal lines giving a mosaic appearance
What are reversal lines (Paget’s)
- junctions where there has been reversal of osteoclastic resorption to osteoblastic deposition
What are complications of paget’s
- infection
- MRONJ - px usually on implicated medication
- tumour - rare complications = osteosarcoma and other bone tumours
What is the main benign bone tumour
osteoma
How does osteoma present
- slow growth
- excess growth of cortical bone
- usually solitary but can have multiple
What is multiple osteomas a sign of
Gardner’s syndrome
genetic disorder
What is an important feature of gardner’s syndrome that should be checked out
polyposis coli
tendency to become malignant
refer to GI
What is the main malignant bone tumour
- osteosracoma
How does osteosarcoma present
- rare in jaws
- usually seen in younger px, if elderly, consider pagets
- usually presents as swelling with pain adn paraesthesia
- may be a giant osteoid sarcoma
- often v active growth
What is ossifying fibroma
- well demarcated, occasionally encapsulated benign neoplasm
What is the clinical presentation of ossifying fibroma
- slow growing
- wide age range
- mainly mandible
- radiologically well defined - may have calcium deposits
How does ossifying fibroma present histolofically
- pretty much same as fibrous dysplasia
- cellular fibrous tissue containing immature bone and acellular calcification
What differentiates ossifying fibroma to fibrous dysplasia
fibrous dysplasia does not have well defined margins, ossifying fibroma does
What are the main 2 cementum lesions
cementoblastoma
cemento-osseous dysplasia
What is cementoblastoma
neoplasm attached to root
histologically same as osteoblastoma
What is cementoosseous dysplasia unlikely to be
neoplastic
What are the 3 types of cemento-osseous dysplasia
peripheral
focal
florid
What is peripheral COD
- usually lower incisors effected (teeth are vital)
- starts as well defined radiolucency resembling PA granuloma
What is focal COD
- localised
- no more than 1 in 1 area
What is florid COD
widespread
