Benign & Malignant Bone Tumours

Question 1

State at least 3 differences between benign and malignant bone tumours

Answer 1

Benign = no periosteal reaction, malignant = acute periosteal reaction
Benign = thick endosteal reaction, malignant = broad border between lesion and normal bone
Benign = well-developed bone formation, malignant = varied bone formation
Benign = intraosseus and even calcification, malignant = extraosseus and irregular calcification

Question 2

Describe the acute periosteal reaction seen in malignant bone tumours

Answer 2

Cortex showing Codman’s triangle (triangular area of new subperiosteal bone created when the periosteum is raised away from the bone), onion skin, sunburst

Question 3

State the typical age of onset of osteosarcoma

Answer 3

Adolescence

Question 4

State the typical age of onset of Ewing’s sarcoma

Answer 4

<20 years

Question 5

State the typical age of onset of giant cell tumours

Answer 5

20-40 years

Question 6

State the typical age of onset of chondrosarcoma

Answer 6

> 40 years

Question 7

State the most common site of osteosarcoma

Answer 7

Knee

Question 8

State the most common site of giant cell tumours

Answer 8

Epiphysis of knee

Question 9

State the most common sites of Ewing’s sarcoma

Answer 9

Long bones, pelvis

Question 10

State the most common sites of chondrosarcomas

Answer 10

Axial skeleton, femur, tibia, pelvis

Question 11

Describe the histological appearance of osteosarcoma

Answer 11

Malignant mesenchymal cells, positive for ALP

Question 12

Describe the histological appearance of chondrosarcoma

Answer 12

Malignant chondrocytes

Question 13

Describe the histological appearance of Ewing’s sarcoma

Answer 13

Sheets of small round cells positive for CD99. Genetic analysis shows t(11;22)

Question 14

Describe the histological appearance of giant cell tumours

Answer 14

Osteoclast-type multinucleate giant cells on background of spindle or ovoid cells

Question 15

Describe the x-ray appearance of osteosarcoma

Answer 15

Elevated periosteum (Codman’s triangle), sunburst appearance

Question 16

Describe the x-ray appearance of chondrosarcoma

Answer 16

Lytic lesion with fluffy calcification

Question 17

Describe the x-ray appearance of Ewing’s sarcoma

Answer 17

Onion skinning of periosteum

Question 18

Describe the x-ray appearance of giant cell tumours

Answer 18

Lytic or lucent lesions right up to the articular surface

Question 19

State the most common sites of osteoid osteoma

Answer 19

Tibial diaphysis, proximal femur

Question 20

State the most common sites of osteoma

Answer 20

Head and neck

Question 21

State the most common sites of enchondroma

Answer 21

Hands

Question 22

State the most common sites of osteochondroma

Answer 22

Metaphysis of long bones near tendon attachment sites

Question 23

State the most common site of fibrous dysplasia

Answer 23

Femur

Question 24

Name 4 malignant bone tumours

Answer 24

Osteosarcoma, chondrosarcoma, Ewin’s sarcoma, giant cell tumour (borderline malignant)

Question 25

Name at least 4 benign bone tumours

Answer 25

Osteoid osteoma, osteoma, endochondroma, osteochondroma, fibrous dysplasia, simple bone cyst, osteoblastoma

Question 26

Describe osteoid osteoma

Answer 26

Small benign bone forming lesion causing pain at night, relieved by aspirin. Histology shows normal bone

Question 27

Define osteoma

Answer 27

Bony outgrowths attached to normal bone. Histology shows normal bone

Question 28

Define Gardner syndrome

Answer 28

Multiple osteomas, gastrointestinal polyps, and epidermoid cysts

Question 29

Define enchondroma

Answer 29

Benign tumours of cartilage. Histology shows normal cartilage

Question 30

Define Maffuci's syndrome

Answer 30

Multiple enchondromas and haemangiomas

Question 31

Define osteochondroma

Answer 31

Cartilage capped bony outgrowrh

Question 32

Define diaphyseal aclasis

Answer 32

Hereditary multiple exostoses with short stature and bone deformities

Question 33

Define fibrous dysplasia

Answer 33

Replacement of bone by fibrous tissue. 'Chinese letters' (misshapen bone trabeculae) on histology

Question 34

Describe the features of Albright syndrome

Answer 34

Polyostotic fibrous dysplasia with café au lait spots and precocious puberty

Question 35

Describe the x-ray appearance of osteoid osteoma

Answer 35

Radiolucent nidus with sclerotic rim - Bullseye appearance

Question 36

Describe the x-ray appearance of enchondroma

Answer 36

Lytic lesion with cotton wool calcification. O ring sign

Question 37

Describe the x-ray appearance of osteochondroma

Answer 37

Well defined bony protuberance, cartilage capped - mushroom appearance

Question 38

Describe the x-ray appearance of fibrous dysplasia

Answer 38

Soap bubble osteolysis, Shepherd's crook deformity

Question 39

Describe the x-ray appearance of osteoblastoma

Answer 39

Speckled mineralisation