Bone tumours

Question 1

Site of Osteosarcoma?

Answer 1

Metaphysis of long bones

classically distal femur and proximal tibia

Question 2

Site of Ewings sarcoma?

Answer 2

Diaphysis of long bones

pelvis, ribs, scapula, long bones, vertebrae

Question 3

What is the most common primary bone tumour in adolescence?

Answer 3

osteosarcoma

Question 4

What are the RF for osteosarcoma?

Answer 4

RB1 mutation (retinoblastoma survivors)
P53 mutation (Li Fraumani syndrome) x15 risk
PHx Radiation/alkylating agents (common 2nd malignancy)

Question 5

What are the main sites for osteosarcoma?

Answer 5

Distal femur (50%)
Tibia (28%)

Question 6

What do osteosarcomas look like on x-ray?

Answer 6

Lytic, destructive, sclerotic (sunburst)

Question 7

High risk prognostic factors for osteosarcoma? (4)

Answer 7

metastatic disease
axial location
large tumour size
poor response to chemotherapy

Question 8

Where do osteosarcomas metastasise to?

Answer 8

lung

Question 9

Percentage of Ewings sarcoma which are metastatic at diagnosis?

Answer 9

20%

Question 10

What are the features of Ewings sarcoma on x-ray?

Answer 10

Destruction of cortex
Elevation of periosteum
Infiltration of surrounding tissue
“Onion skin”

Question 11

Most common genetic anomaly associated with Ewings sarcoma?

Answer 11

t(11:22) - 90%