Benign Bone Tumours

Question 1

What is an osteochondroma?

Answer 1

Bony outgrowth on external surface with a cartilaginous cap

Question 2

Presentation of osteochondroma?

Answer 2

No problems apart from local pain

Question 3

Risk of osteochondroma?

Answer 3

1% risk of malignant transformation

Question 4

How is multiple osteochondromata inherited?

Answer 4

Autosomal dominant hereditary disorder

Question 5

What is enchondroma?

Answer 5

Intramedullary & usually metaphyseal cartilaginous tumour

Question 6

What failure is associated with enchondroma?

Answer 6

Failure of normal enchondral ossification at the growth plate

Question 7

Symptoms of enchondroma?

Answer 7

Usually asymptomatic

-can weaken bone (pathological fracture)

Question 8

Where are enchondromas usually?

Answer 8

Femur
Humerus
Tibia
Small bones of Hand & Feet

Question 9

What does an enchondroma lesion usually look like?

Answer 9

Usually lucent but can undergo mineralization- Patchy sclerotic appearance

Question 10

Treatment of enchondroma?

Answer 10

Fracture healed and risk of impending fracture- curettage & filled with bone graft

Question 11

What is curettage?

Answer 11

Bone scraped out

Question 12

What is simple bone cyst?

Answer 12

Single cavity, benign fluid filled cyst

Question 13

What is the probable cause of a simple bone cyst?

Answer 13

Probably a growth defect from the physis

Question 14

Presentation of simple bone cyst?

Answer 14

Can be asymptomatic & an incidental finding on x-ray

-Can cause weakness resulting in pathological fracture

Question 15

Treatment of a simple bone cyst?

Answer 15

Curettage and bone grafting +/- stabilization

Question 16

Another term for simple bone cyst?

Answer 16

Unicameral bone cyst

Question 17

What is an aneurysmal bone cyst?

Answer 17

Lots of blood/serum filled chambers

Question 18

What are aneurysmal bone cysts due to?

Answer 18

Small arteriovenous malformation

Question 19

Where do aneurysmal bone cysts appear?

Answer 19

In metaphyses of many different long bones, flat bones

(Ribs, skulls) and vertebral bodies

Question 20

Presentation of aneurysmal bone cysts?

Answer 20

Locally aggressive

• Cortical expansion & destruction
• Painful, pathological fracture

Question 21

Treatment of aneurysmal bone cysts?

Answer 21

Curettage & grafting/bone cement

Question 22

Where do giant cell tumours affect?

Answer 22

Metaphyseal region
-Involve epiphysis & can extend to the subchondral bone adjacent to the joint

-Knee, distal radius, also other long bones: pelvis, spine

Question 23

Presentation of giant cell tumour?

Answer 23

• Painful

- May cause pathological fracture

Question 24

What does a giant cell tumour look like on x-ray?

Answer 24

Soap bubble appearance

Question 25

Where do 5% of giant cell tumours metastasize to?

Answer 25

The lung

Question 26

What type of cell do giant cell tumours consist of?

Answer 26

Multi-nucleate giant cells

Question 27

Treatment of giant cell tumours?

Answer 27

Intralesional excision with phenol, bone cement or liquid nitrogen
-Destroy remaining tumour material & reduce risk of recurrence

Question 28

Treatment of very aggressive lesions with cortical destruction?

Answer 28

May need replacement

Question 29

When does fibrous dysplasia present?

Answer 29

Adolescence

Question 30

What causes fibrous dysplasia?

Answer 30

Genetic mutation

Question 31

What is fibrous dysplasia?

Answer 31

Lesions in fibrous tissue & immature bone

Question 32

Meaning of monostotic?

Answer 32

Affects 1 bone

Question 33

Meaning of polyostotic?

Answer 33

Affects more than one bones

Question 34

Presentation of fibrous dysplasia?

Answer 34

• Angular deformities
• Wider bone
• Thickened cortices
• Stress fractures can occur
• Shepherd’s crook deformity (proximal femur)

Question 35

Treatment of fibrous dysplasia?

Answer 35

• Biphosphonates may reduce pain
• Pathologic fractures should be stabilized with internal fixation & cortical bone grafts
• Simple intralesional excision has a high recurrence rate

Question 36

What is osteoid osteoma?

Answer 36

Small nidus of immature bone surrounded by an intense sclerotic halo

Question 37

When does osteoid osteoma present?

Answer 37

Adolescence

Question 38

Common sites of osteoid osteoma?

Answer 38

Proximal femur
Diaphysis of long bones
Vertebrae

Question 39

Clinical features of osteoid osteoma?

Answer 39

Intense constant pain (worse at night due to intense inflammatory response)

Question 40

Treatment of osteoid osteoma?

Answer 40

May resolve spontaneously over time

Some cases require CT quidded radiofrequency ablation/ en bloc excision