Primary Bone tumors

Question 1

Mutation in Achondroplasia

Answer 1

Constitutive activation of fibroblast growth factor receptor (FGFR3)

inhibits chondrocyte proliferation

Question 2

Most common malignant primary bone tumor in children

Answer 2

Osteosarcoma

Osteogenic sarcoma

Question 3

Most common benign bone tumor

Answer 3

Osteochondroma

Question 4

11;22 translocation

Answer 4

Ewing sarcoma

causing fusion protein EWS- FLI 1

Question 5

Rb mutation

Answer 5

Osteosarcoma

Question 6

“sunburst” pattern on x-ray

Answer 6

Osteosarcoma

Question 7

“soap bubble” appearance on x-ray

Answer 7

Giant Cell Tumor
Osteogenic sarcoma

“clean like soap”

Question 8

“Onion skin” appearance of bone

Answer 8

Ewing Sarcoma

Question 9

May actually be a hamartoma

Answer 9

Osteochondroma

“chunk of bone”

Question 10

Codman’s triangle on x-ray

Answer 10

Osteosarcoma

from elevation of periosteum

Question 11

What causes short limbs in Achondroplasia

Answer 11

Failure of longitudinal bone growth (enchondral fusion

Question 12

How is achondroplasia passed on

Answer 12

> 85% of mutations occur sporadically

autosomal dominant with full penetrance (homozygosity lethal)

Question 13

Males

Answer 13

Osteochondroma

Question 14

20-40 years old

Answer 14

Giant Cell Tumor

Osteoclastoma

Question 15

Multinucleated giant cells

Answer 15

Giant Cell tumor

Osteoclastoma

Question 16

Bimodal distribution: 10-20 years (primary)

>65 (secondary)

Answer 16

Osteosarcoma (osteogenic sarcoma)

Question 17

Boys

Answer 17

Ewing Saroma