Bone Tumours

Question 1

what is an osteoma?

Answer 1

benign overgrowth of bone
most typically on skull

Question 2

what is osteoma a/w?

Answer 2

gardner’s syndrome (variant of FAP)

Question 3

what is an osteochondroma?

Answer 3

most common benign bone tumour
cartilage-capped bony projection on the external surface of a bone

Question 4

who is osteochondroma more common in?

Answer 4

males
usually <20y

Question 5

what is another term for osteochondroma?

Answer 5

exotosis

Question 6

what is a giant cell tumour?

Answer 6

tumour of multinucleated giant cells within a fibrous stoma

Question 7

peak incidence of giant cell tumour?

Answer 7

20-40y

Question 8

what do giant cell tumour affect?

Answer 8

frequently in epiphyses of long bones

Question 9

what do x-rays show in giant cell tumours?

Answer 9

double bubble or soap bubble appearance

Question 10

list the benign bone tumours

Answer 10

osteochondroma
osteoma
giant cell tumour

Question 11

list the malignant tumours

Answer 11

osteosarcoma
ewing’s sarcoma
chondrosarcoma

Question 12

what is an osteosarcoma?

Answer 12

most common primary malignant bone tumour

Question 13

who do osteosarcomas occur in?

Answer 13

children and adolescents
mostly males

Question 14

where do osteosarcomas often occur?

Answer 14

metaphyseal region of long bones before epiphyseal closure

40% femur (distal)
20% tibia (proximal)
10% humerus

Question 15

what do x-rays show in osteosarcoma?

Answer 15

periosteal reaction with codman’s triangle
sunburst appearance

Question 16

mutation in what gene increases risk of osteosarcoma?

Answer 16

rb gene
hence a/w retinoblastoma

Question 17

what are other predispoing factors to osteosarcoma (other than rb gene)?

Answer 17

paget’s
radiotherapy

Question 18

what is ewing’s sarcoma?

Answer 18

small round blue cell tumour
tends to cause severe pain

Question 19

who does ewing’s sarcoma mostly affect?

Answer 19

children and adolescents

Question 20

where does ewing’s sarcoma commonly occur?

Answer 20

diaphysis of pelvis and long bones

Question 21

what is ewing’s sarcoma a/w?

Answer 21

t(11;122) translocation
results in EWS-FLI1 protein (i.e. the gene product) - can be detected on fine needle aspiration

Question 22

what does x-ray of ewing’s sarcoma show?

Answer 22

onion skin periosteal reaction

Question 23

what is chondrosarcoma?

Answer 23

malignant tumour of cartilage

Question 24

what does chondrosarcoma affect?

Answer 24

most commonly, axial skeleton

Question 25

who does chondrosarcoma affect?

Answer 25

more common in middle age (>40)

Question 26

what is used to score predict risk of fracture with secondary bone tumours?

Answer 26

mirel scoring

Question 27

what do secondary bone tumours look like on x-ray?

Answer 27

appearance depends on primary
- prostate -> sclerotic
- breast -> lytic

Question 28

bone profile for secondary bone tumours?

Answer 28

elevated ca and ALP

Question 29

mx for secondary bone tumours?

Answer 29

radiotherapy
prophylactic fixation
analgesia

Question 30

how does osteosarcoma present?

Answer 30

warm painful swelling
most commonly at knee

Question 31

how does ewing’s sarcoma present?

Answer 31

systemic symptoms - fever, anaemia
bloods - raised ESR, WCC

Question 32

how does chondrosarcoma present?

Answer 32

pain
a lump

Question 33

what does x-ray of chondrosarcoma show?

Answer 33

lytic lesion with ‘fluffy popcorn calcification’