Bone Tumours

Question 1

What are osteogenic cells?

Answer 1

Bone stem cells located in the periosteum and endosteum. These cells differentiate into osteoblasts.

Question 2

What are osteoblasts?

Answer 2

Cells that lay bone matrix around themselves (“build bone”) until they become trapped and become osteocytes.

Question 3

What are osteoclasts?

Answer 3

Derived from monocytes, their function is to resorb bone in response to hormonal signalling (“break down bone”).

Question 4

What are osteocytes?

Answer 4

These are mature osteoblasts that maintain the integrity of bone tissue.

Question 5

Describe the 6 classifications of bone tumours according to histology.

Answer 5

Osteogenic
Chondrogenic 
Giant-cell tumour 
Marrow
Tutor-like lesions
Secondary

Question 6

Describe the 4 classifications of bone tumours according to location.

Answer 6

Epiphysis
Metaphysis
DIaphysis
Flat bones

Question 7

Name some examples of bone cancers that would form at the epiphysis.

Answer 7

Giant cell tumour, chondroblastoma, clear cell chondrosarcoma, osteochondroma

Question 8

Name some examples of bone cancers that would form at the metaphysis.

Answer 8

Conventional osteosarcoma, Ewing sarcoma, primary chondrosarcoma, osteochondroma, chondroma, osteoid osteoma, giant cell tumour

Question 9

Name some examples of bone cancers that would form at the diaphysis.

Answer 9

Periosteal osteosarcoma, Ewing sarcoma, osteoid osteoma, primary chondrosarcomas, chondroma, multiple myeloma

Question 10

Name some examples of bone cancers that would form at the flat bones.

Answer 10

Ewing sarcoma, secondary chondrosarcoma

Question 11

Why do metaphyseal lesions tend to be either secondary (metastatic) bone tumours or multiple myeloma?

Answer 11

• Extensive blood supply

- Presence of red marrow i.e. haemopoetic cells

Question 12

Describe the difference between an epiphyseal lesion in a skeletally mature individual vs a skeletally immature individual.

Answer 12

An epiphyseal lesion in a skeletally mature individual suggests a giant-cell tumour whereas an epiphyseal lesion in a skeletally immature individual points to chondroblastoma.

Question 13

Describe how a patient with a bone tumour would present.

Answer 13

Typical symptoms of bone tumours include:

Pain (progressive, activity-related, at rest or worse at night)
Soft tissue or bony swellings
Limp
B symptoms: weight loss, fever and night sweats

Question 14

Describe the positive clinical findings of an examination of a patient with a bone tumour.

Answer 14

Typical clinical findings in bone tumours include:

Neurovascular dysfunction: paraesthesia and reduced temperature in the affected limb (a large bone tumour can press on surrounding nerves and vessels)
Swelling: may be painless or tender (note the size and consistency)
Deformity
Limp
Local mechanical problems (painful movements or decreased range of joint motion)
Signs of a fracture
Systemic symptoms (e.g. unintentional weight loss and fatigue)
Local lymphadenopathy

Question 15

Name the clinical signs used to determine wether a bone lesion is benign or malignant on X-ray.

Answer 15

Boarder
zone of transition
condition of the cortex
pattern of periosteal reaction
extension
matrix
skip lesions

Question 16

Name some complications of bone biopsy.

Answer 16

Tumour contamination
Haemorrhage
Wound breakdown
Infection
Pathological fracture

Question 17

Name 2 staging systems for bone tumours.

Answer 17

There are currently two staging systems used for bone tumours: TNM and Enneking systems.

Question 18

Describe the Enneking staging system for bone tumours.

Answer 18

Grading is from G0 to G2:

G0 – non-cancerous (benign)
G1 – low-grade tumour
G2 – high-grade tumour
Bone tumours are also divided into 3 stages: stage 1 is low grade, stage 2 is high grade and stage 3 denotes that the tumour has metastasised.

Stages 1 and 2 are further divided into A and B:

A – the tumour is contained within the bone
B – the tumour has broken through the bone wall