Bone and soft tissue tumours

Question 1

What kind of bone tumour is a >50 y/o patient likely to have?

Answer 1

A metastatic bone tumour i.e. secondary malignant tumour

Question 2

What types of bone tumours can you get?

Answer 2

Benign:

• Osteoid osteoma or osteoblastoma
• These usually form in the proximal femur but also other sites
• Quite rare

Malignant:

• osteosarcoma

Question 3

What is a Sarcoma?

Answer 3

A malignant tumour arising from connective tissues

• Commonly spreads via the blood to the lungs

Question 4

Vacular tissue tumours (benign and malignant)

Answer 4

Benign:

• Haemangioma, aneurysmal bone cyst

Malignant:

• Angiosarcoma = rare

Question 5

Name 3 malignant bone marrow tumours

Answer 5

• Ewing’s sarcoma - childhood cancer
• Lymphoma
• Myeloma

Question 6

Describe what a simple bone cyst is?

Answer 6

• A benign tumour-like lesion often occuring in children
• They are little fluid-filled holes that form in the cortex of the bone
• They weaken the bone which can lead to fractures (hence why patients often present with a fracture)
• After the fracture heals the cysts tend to disappear

Question 7

What are the most common primary bone tumours in the UK?

Answer 7

1. Osteosarcoma
2. Chondrosarcoma - malignant cartilage tumour
3. Ewing’s tumour

Question 8

What is the commonest primary malignant bone tumour in younger patients?

Answer 8

Osteosarcoma

Question 9

What is the commonest primary malignant “bone” tumour in older patient?

Answer 9

Myeloma

Question 10

Typical presentation of patient with a bone tumour?

Answer 10

• PAIN - pain at rest/activity related/at night, deep-seated and boring pain
• A mass if progressed - malignant mass would be hard, craggy, immobile/fixed etc
• Abnormal x-ray - often incidental finding

Question 11

What are some common characteristics of pain associated with bone tumours?

Answer 11

• Pain may be activity related – this might be due to weakening of the bone and therefore any stress placed on the bone puts it at risk of fracture. This is associated with malignant tumours and also benign tumours but only if they are large enough
• Progressive pain at rest & night

Question 12

Osteoid Osteoma

Answer 12

Benign bone tumour

• Tiny bone forming tumours called ‘nidus’’ - (tumour tissue in centre with bone surrounding it)
• These can create intense pain at night – until the nidus is removed that pain will continue

Question 13

What sorts of things should you look out for during an examination of a patient with unusual mass? (9)

Answer 13

• General health – are they fit and well?
• Measurements of mass
• Location of mass
• Shape of mass
• Consistency – hard mass is bad news
• Mobility – fixed to deeper tissue or the skin above it?
• Tenderness
• Local temperature change – indicating vascularity
• Neuro-vascular deficits – changes in sensation, power etc due to invasion of nerves etc

Question 14

During examination, what signs indicate that it might be more sinister i.e. a malignant bone tumour?

Answer 14

• Rapidly growing mass
• Mass will be hard, craggy, fixed, indistinct margins
• Non-tender to palpation but associated with deep ache

Question 15

What is the best imaging tool for looking at bone lesions?

Answer 15

X-ray

Question 16

Name some lesions that are associated with bone tumours that you should look out for on an x-ray (3)

Answer 16

• Calcification - synovial sarcoma (calcification of the thickened synovium)
• Myositis ossificans - bone tissue forms inside muscle or other soft tissue after an injury - as a result of trauma, not a tumour
• Phleboliths in haemangioma - small areas of calcifications in blood vessel tumours

Question 17

What features would you expect to see on an x-ray of a benign bone tumour?

Answer 17

• Clear margins
• Surrounding rim of reactive bone
• Cortical expansion can occur with aggressive benign lesions

This x-ray shows a benign tumour on the front of the tibia. Likely to be a benign cyst. Due to weakening of the bone, a fracture has appeared (likely after this fracture heals the bone cyst will disappear). If the cyst is still present after the fracture has healed, surgery may be recommended in order to prevent another fracture.

Question 18

What features would you expect to see on an x-ray of an aggresive bone tumour?

Answer 18

• Less well defined zone of transition between lesion and normal bone (permeative growth)
• If there is cortical destruction = malignancy
• Periosteal reactive new bone growth occurs when the lesion destroys the cortex.
• Codman’s triangle, onion-skinning
• Sunburst pattern - Tumour bursting out of distal femur

X-ray shows an Osteosarcoma of the distal femur. You can also see the sunburst pattern clearly.

Question 19

When is CT imaging used?

Answer 19

• Primarily used for staging of secondary metastases (i.e. the lungs)
• Assessing ossification and calcification
• Assessing the integrity of cortex
• Best for assessing nidus in osteoid osteoma – location etc

Question 20

What are isotope bone scans used for? (4)

Answer 20

• Staging for skeletal metastasis as you can see how many metastases there are on a single scan
• Also good for multiple benign lesions - osteochondroma, enchondroma, fibrous dysplasia & histiocytosis
• Frequently negative in Myeloma
• Benign also demonstrate increased uptake

Question 21

How does an isotope bone scan work?

Answer 21

• Inject isotope into patient
• The isotope is taken up by active bone and is laid down in bone structure as a calcium substitute.
• Increased uptake where there is increased bone turnover (tumour)
• But there can also be increased uptake in benign lesions

Question 22

Why is MRI the best imaging technique for primary bone and soft tissue tumours?

Answer 22

• Allows you to see size, extent of masses and the anatomical relationships i.e the relationship between a tumour and surrounding blood vessels, nerves etc
• Extent - allows you to see intraosseous (intramedullary) extent of tumour and extraosseous extent i.e how far it extends into soft tissue
• Specific for Lipoma, haemangioma, haematoma or PVNS – they have specific signals on MRI so you know definite diagnosis
• Can show if there is any joint involvement
• However, it’s not very good at differentiating between benign vs. malignant

Question 23

What is the main role of Angiography in terms of bone tumour management nowadays?

Answer 23

• Imaging prior to tumour embolisation – tumours with a high vascularity (i.e. renal tumour secondaries to bone) will be embolised prior to surgery
• Embolisation shuts down the blood supply to a tumour reducing blood loss during surgical resection

Question 24

What is the best way to differentiate between a benign or malignant tumour?

Answer 24

Biopsy - needle core or open

Question 25

What are the cardinal features of a malignant bone tumour? i.e. the major clinical signs/symptoms by which a diagnosis is made.

Answer 25

• Increasing pain
• Unexplained pain
• Deep-seated boring nature
• Night pain
• Difficulty weight-bearing
• Deep swelling

Question 26

Osteosarcoma:

Incidence, symptoms and treatment

Answer 26

M>F, 10-30 y/o - common in this age group

Most common site = the distal femur and proximal tibia

Symptoms:

• pain
• loss of function – due to discomfort. May have a limp or stiff back (red flag in child/young person)
• swelling i.e tumour - generally diffuse in malignancy
• pathological fracture - primary bone tumour (benign or malignant) is actually quite a rare cause
• joint effusion
• deformity
• neurovascular effects
• systemic effects of neoplasia, weight loss, low grade temp, loss of appetite

Treatment:

Goal is to make free of disease and improve QOL

• Chemo – shrink tumour
• Surgery – excise tumour
• May do radiotherapy

Question 27

What red flag signs should you be wary of in regards to any tumour/swelling?

Answer 27

If the swelling is:

• rapidly growing
• hard, fixed, craggy surface, indistinct margins
• non-tender to palpation, but assoc. with deep ache, esp. worse at night
• BEWARE – may be painless
• Recurred after previous excision

It is likely a malignancy

Question 28

Examples of soft tissues (9)

Answer 28

• Muscles
• Tendons
• Ligaments
• Fascia
• Nerves
• Fibrous tissues
• Fat
• Blood vessels
• Synovial membranes

Question 29

What are the most common sites for secondary metastatic tumours?

Answer 29

1. Lung
2. Liver
3. Bone

Question 30

Which sites in the bony skeleton do secondary tumours that spread to bone most commonly affect? (6)

Answer 30

1. Vertebrae
2. Proximal femur
3. Pelvis
4. Ribs
5. Sternum
6. Skull

Question 31

What are the most common primary cancers that metastasise to bone? (7)

Answer 31

1. Lung
2. Breast
3. Prostate
4. Kidney
5. Thyroid
6. GI tract
7. Melanoma

Question 32

How are pathalogical fractures prevented?

Answer 32

• Identify them through things like routine bone scans
• Early chemo i.e. in breast cancer to reduce number of secondaries
• Radiotherapy where secondaries are identified
• When pain is increasing – real risk of fracture – so if we see a tumour >2.5 cm on an x-ray then we know that will often lead to fracture – prophylaxis treatment – fixation to stop the fracture
• Often add bone cement to increase stability

Question 33

What scoring system is used to identify patients who would benefit from prophylactic fixation due to having a high risk of pathological fracture?

Answer 33

Mirel’s scoring system

• Looks at site, pain, lesion and size
• If score is 8 or more – recommend prophylaxis fixation before radiotherapy

Question 34

What must be done before a surgical procedure to remove a tumour?

Answer 34

Embolisation of the tumour and then a wait of 48 hours before surgery to prevent catastrophic bleeding

Question 35

Why is size so important in differentiating between a benign or malignant soft tissue tumour?

Answer 35

• If the swelling is <5cm it is more likely to be a lipoma (benign)
• Anything >5cm is likely to be a sarcoma (malignant)
• So if it is a large, deep seated swelling – you can be quite sure that it is a sarcoma

Question 36

Common features of a malignant soft tissue tumour

Answer 36

• Painless
• Mass deep to deep fascia
• Any mass >5cm
• Any fixed, hard or indurated mass
• Any recurrent mass