Bone tumours

Question 1

Osteosarcoma

Answer 1

MALIGNANT
Teens
Knee
Malignant mesenchymal cells
ALP +ve
Elevated periosteum (Codman's triangle)
sunburst appearance

Question 2

Chrondosarcoma

Answer 2

MALIGNANT
>40 yrs
Axial skeleton 
Femur/tibia/ pelvis
Malignant chondrocytes
Lytic lesion with fluffy calcification

Question 3

Ewing’s sarcoma

Answer 3

MALIGNANT
<20yrs
Long bones, pelvis
Sheets of small round cells CD99 +ve
T 11:22 translocation
Onion skinning of periosteum

Question 4

Giant cell

Answer 4

BORDERLINE MALIGNANT
20-40yrs F>M
Knee- epiphysis
Osteoclast-type multinucleate giant cells on background of spindle/ovoid cells
Lytic/lucent lesions right up to articular surface

Question 5

Osteoid osteoma

Answer 5

BENIGN
Teens
More common in boys
Tibia diaphysis/ Proximal Femur
Small benign bone forming lesion, night pain relieved by aspirin
Normal bone, arises from osteoblasts
Radiolucent nidus with sclerotic rim ‘Bull’s-eye’

Question 6

Osteoma

Answer 6

BENIGN
Middle age
Bony outgrowths attached to normal bone
Gardner syndrome:
GI polyps + multiple osteomas + epidermoid cysts
Normal bone

Question 7

Endochrondoma

Answer 7

BENIGN
Middle age
Hands 43% Ie Ends so often in the hands
Benign tumours of cartilage
Ollier’s syndrome =
multiple enchondromas
Maffuci’s syndrome =
multiple enchondromas + haemangiomas

Normal cartilage
Lytic lesion
Cotton wool calcification
Expansile, O ring sign

Question 8

Osteochondroma

Answer 8

BENIGN
Most common benign
Adolescence
Metaphysis of long bones near tendon attachment sites
Cartilage capped bony outgrowth
Diaphyseal aclasis/ hereditary multiple exostoses =
multiple exostoses + short stature + bone deformities

Cartilage capped bony outgrowth
Well defined bony protuberance from bone
Cartilage capped bony spur on surface of bone ‘mushroom’ on xray

Question 9

Fibrous dysplasia

Answer 9

F>M
Middle age
Femur & ribs
A bit of bone is replaced by fibrous tissue
Albright syndrome =
polyostotic dysplasia + café au lait spots + precocious puberty

Chinese letters (misshapen bone trabeculae)
Soap bubble osteolysis Shepherd’s crook deformity

Question 10

Simple bone cyst

Answer 10

Humerus or femur
Fluid filled unilocular
Lytic well defined

Question 11

Osteoblastoma

Answer 11

Similar to osteoid osteoma

Speckled mineralisation

Question 12

Benign

Answer 12

No periostea reaction
Thick endosteal reaction
Well developed bone formation
Inraosseous and even calcification

Question 13

Malignant

Answer 13

Broad boarder between lesion and normal bone
Varied bone formation
Extraosseous and irregular calcification
Acute periosteal reaction- Codman’s triangle, sunburst appearance