Bone Tumours Flashcards
what is an osteoma?
benign overgrowth of bone
most typically on skull
what is osteoma a/w?
gardner’s syndrome (variant of FAP)
what is an osteochondroma?
most common benign bone tumour
cartilage-capped bony projection on the external surface of a bone
who is osteochondroma more common in?
males
usually <20y
what is another term for osteochondroma?
exotosis
what is a giant cell tumour?
tumour of multinucleated giant cells within a fibrous stoma
peak incidence of giant cell tumour?
20-40y
what do giant cell tumour affect?
frequently in epiphyses of long bones
what do x-rays show in giant cell tumours?
double bubble or soap bubble appearance
list the benign bone tumours
osteochondroma
osteoma
giant cell tumour
list the malignant tumours
osteosarcoma
ewing’s sarcoma
chondrosarcoma
what is an osteosarcoma?
most common primary malignant bone tumour
who do osteosarcomas occur in?
children and adolescents
mostly males
where do osteosarcomas often occur?
metaphyseal region of long bones before epiphyseal closure
40% femur (distal)
20% tibia (proximal)
10% humerus
what do x-rays show in osteosarcoma?
periosteal reaction with codman’s triangle
sunburst appearance
mutation in what gene increases risk of osteosarcoma?
rb gene
hence a/w retinoblastoma
what are other predispoing factors to osteosarcoma (other than rb gene)?
paget’s
radiotherapy
what is ewing’s sarcoma?
small round blue cell tumour
tends to cause severe pain
who does ewing’s sarcoma mostly affect?
children and adolescents
where does ewing’s sarcoma commonly occur?
diaphysis of pelvis and long bones
what is ewing’s sarcoma a/w?
t(11;122) translocation
results in EWS-FLI1 protein (i.e. the gene product) - can be detected on fine needle aspiration
what does x-ray of ewing’s sarcoma show?
onion skin periosteal reaction
what is chondrosarcoma?
malignant tumour of cartilage
what does chondrosarcoma affect?
most commonly, axial skeleton
who does chondrosarcoma affect?
more common in middle age (>40)
what is used to score predict risk of fracture with secondary bone tumours?
mirel scoring
what do secondary bone tumours look like on x-ray?
appearance depends on primary
- prostate -> sclerotic
- breast -> lytic
bone profile for secondary bone tumours?
elevated ca and ALP
mx for secondary bone tumours?
radiotherapy
prophylactic fixation
analgesia
how does osteosarcoma present?
warm painful swelling
most commonly at knee
how does ewing’s sarcoma present?
systemic symptoms - fever, anaemia
bloods - raised ESR, WCC
how does chondrosarcoma present?
pain
a lump
what does x-ray of chondrosarcoma show?
lytic lesion with ‘fluffy popcorn calcification’
