Cancer

Question 1

Osteoid Osteoma

Answer 1

Adolescent

Tibia/femur

Small benign bone forming lesion, night pain relived with aspirin

Normal bone on histology

Radiolucent midus with sclerotic rim

Question 2

Osteoma

Answer 2

Middle Age

Head + neck

Bony outgrowths attached to normal bone
Gardener syndrome = GI polyps + osteomas + epidermoid cysts

Normal bone

Question 3

Enchondroma

Answer 3

Middle age

Hands 40%

Benign tumours of cartilage
Ollier’s syndrome = multiple enchondromas
Maffuci’s syndrome = multpile enchondromas + haemangiomas

Normal Cartilage

Lytic lesion, cotton wool calcification
Expansile O-ring sign

Question 4

Osteochondroma

Answer 4

Adolescent

Long bones

Cartilage capped bony outgrowth

Well defined bony protuberance from bone on X-ray

Question 5

Fibrous Dysplasia

Answer 5

F>M

Femur

Bone replaced by fibrous tissue

‘Chinese letters’ seen on histology

Soap bubble osteolysis
Shepherd’s crook deformity

Question 6

Simple bone cyst

Answer 6

Humerus/femur

Fluid filled, unilocular

Lytic but well defined on X-ray

Question 7

Osteoblastoma

Answer 7

Similar to osteoid osteoma

Speckled mineralisation on X-ray

Question 8

Giant Cell tumour

Answer 8

Borderline malignancy

Epiphysis with metaphyseal extension

F>M

Osteoclasts on a background of spindle/ovoid cells

Locally aggressive

Lytic picture on x-ray

Question 9

Osteosarcoma

Answer 9

Adolescent

Knee 60%

Malignant mesenchymal cells, ALP +ve

Elevated periosteum (Codman's triangle)
Sunburst appearance

Question 10

Chondrosarcoma

Answer 10

> 40

Axial skeleton
Femur/tibia/pelvis

Malignant chondrocytes

Lytic lesions with fluffy calcifications

Question 11

Ewing’s sarcoma

Answer 11

<20

Long bones/pelvis

Sheets of small round cells
CD99 +ve
T11:22 translocation

Onion skinning of periosteum