Week 1 - F - Malignant bone tumours - Osteosarcoma, chondrosarcoma, fibrous cancer, Ewing's sarcoma, metastatic

Question 1

What age group do malignant primary bone tumours arise in? What are they often misdiagnosed for and what does this cause?

Answer 1

Malignant primary bone tumours tend to occur in younger patients (although can occur at any age)

They are often misdiagnosed for muscular pains and presentation is often late in the disease process meaning metastases may have occurred

Question 2

Malignant primary bone tumours are very rare when considered alongside other forms of primary malignancy. On the other hand, metastatic cancer affecting the skeleton is common. What are certain red flags that may arouse suspicion of cancer of the bone?

Answer 2

Constitutional (systemic) symptoms - weight loss, loss of appetite, fatigue

Unexplained skeletal pain in patients less than 25 years old or over 60 years old

Constant bone pain that may be severe and is worse at night

Question 3

If a patient does have certain red flags in their histories which arouse suspicion of cancer of the bone, which investigation should be warranted as a minimum?

Answer 3

Any red flags or any unexplained persistent pain warrants investigation with at least an x‐ray

Question 4

Malignant bone tumours show aggressive and destructive signs on xray Name the 4 main signs seen on xray when there is bone cancer?

Answer 4

Bone cancer xray signs:

Cortical bone destruction

New bone formation (sclerosis as well as lysis from destruction)

Periosteal reaction (raised perisoteum producing bone)

Soft tissue swelling (due to extension into the the surrounding soft tissue envelope)

Question 5

What investigations are useful to detemrine the local extent of the bone tumour? What is the staging investigations used for bone cancer?

Answer 5

MRI and CT are useful to determine the local extent of tumour and the involvement of muscle, nerves and vessels

Staging investigations for bone cancer usually include bone scan and CT chest

Question 6

What is the usual primary treatment of primary malignant bone tumours? What is carried out prior to this treatment for histological diagnosis and grading?

Answer 6

The treatment of primary bone tumours usually involves surgery to remove the tumour and surrounding tissue to reduce the risk of recurrence. - adjuvant therapy depends on the tumour

Biopsy is required for histological diagnosis and grading prior to definitive surgery. In general the biopsy should normally be performed in the specialist centre where definitive surgery is performed

Question 7

What is the most common form of primary bone tumour? What age group does it typically arise in? What are the main bones involved in 60% of cases?

Answer 7

The most common form of primary bone tumour is an osteosarcoma - named according to the fact it is a malignant tumour producing bone

Most cases are seen in younger age groups (adolescents and early adulthood) with 60% involving bones around the knee

Question 8

60% of osteosarcomas involve the bones around the knee. What other sites are common? What is the metastatic spread of osteosarcoma usually?

Answer 8

Other sites for osteosarcoma include the prodimal femur, proximal humerus and pelvis

Metastatic spread is usually haemategnous but can be lymphatic

Question 9

10% of patients with osteosarcoma have pulmonary mets at diagnosis What is the presenting symptom? What is seen on xray? (both these questions are just revision of the previous flashcards)

Answer 9

Presenting symptoms

• * Bone pain in patients 60 (usually for mets)
• * Constant pain, worse at night
• * Systemic - weight loss, loss of appetite, fatigue Xray
• * Cortical bone destruction
• * New bone formation - sclerosis as well as lysis from bone destruction
• * Periosteal reaction - elevated periosteum producing bone
• * Soft tissue swelling - extension of tumour

Question 10

What is the treatment of osteosarcoma?

Answer 10

They are not radiosensitive

Resection of the tumour + adjuvant chemotherapy is treatment of choice

Question 11

What is a chondrosarcoma? Is it as aggresssive as an osteosarcoma? What age group does it tend to occur in?

Answer 11

Chondrosarcoma is a cartilage producing primary bone tumour

* It is less common and less aggressive than a primary bone tumour

* Tends to occur in older men (middle aged)

Question 12

Where do chondrosarcomas tend to be found and what are the presenting symptoms?

Answer 12

Chondrosarcomas tend to be found in the proximal femur and pelvis

It is usually associated with pain or a lump

Question 13

What is the buzzword sign seen on xray in chondrosarcomas?

Answer 13

Popcorn calcification sign is typically seen on xray in chondrosarcoma

Question 14

The prognosis of chondrosarcomas dependant on the histological grade with the majority being low grade. What is the treatment of chondrosarcomas?

Answer 14

Treatment is surgery - they are not radiosensitive and unresponsive to ajduvant chemotherapy thus far

Question 15

What are the two fibrous malignant primary bone tumours?

Answer 15

This would be

* Fibrosarcoma and

* Malignant fibrous histiocytoma

Question 16

When do fibrosarcomas and malignant fibrous histiocytomas occur? What is the difference in the age group affected by the two?

Answer 16

Both fibrosarcomas and malignant fibrous histiocytomas tend to occur in abnormal bone (eg bone infarcts, fibrous dysplasia, paegt’s disease of the bone, post-irradiation)

FIbrosarcomas affect adolescents or young adults

Malignant fibrous histiocytomas tend to occur in middle age

Question 17

What is the 2nd most prevalant primary malignant bone tumour? Which cells does it arise from? What is its prognosis?

Answer 17

Second most prevalent primary malignant bone tumour is Ewing’s sarcoma

Ewing’s sarcoma arises from the primitive cells in the marrow and has the poorest prognosis of all primary malignant bone tumours

Question 18

What is the age range associated with Ewing’s sarcoma? What symptoms may it be associated with and therefore what is it often dmisdiagnosed as?

Answer 18

Ewing’s sarcoma occurs in adolescents (between 10 and 20) It is associated with fever, raised inflammatory markers and a warm swelling - may be mis-diagnosed as osteomyelitis

Question 19

What is the buzzword sign seen on xray in Ewing’s sarcoma?

Answer 19

Radiographs show bone destruction, soft tissue mass and concentric layers of new bone formation

The concentric layers of new bone formtion are seen as Onion-peel sign of Ewing’s sarcoma

Question 20

How are Ewing’s sarcoma treated?

Answer 20

Surgery + adjuvant radio and chemo therapy

Question 21

Put these Primary malignant tumours which commonly metastasize to bone in order of frequency Prostate carcinoma Breast carcinoma Renal cell carcinoma Lung carcinoma Thyroid adenocarcinoma

Answer 21

Primary malignant tumours which commonly metastasize to bone include (in order of frequency):

* Breast carcinoma

* Prostate carcinoma

* Lung carcinoma

* Renal cell carcinoma

* Thyroid adenocarcinoma

Question 22

Are breast cancer metastases sclerotic or lytic?

Answer 22

Breast cancer mets to bone can be blastic (sclerotic) or lytic

Question 23

Do prostate cancer mets to bone produce blastic or lytic mets? What does this mean for fractures? What treatment tends to be carried out for prostate bone mets to reduce fracture risk?

Answer 23

Prostate cancer produces sclerotic metastases and because of the osteoblastic nature, the pathological fractures are more likely to heal

Radiotherapy and hormone manipulation can reduce the fracture risk of a bone metastasis

Question 24

What type of bone lesions does lung cancer give rise to?

Answer 24

Lung cancer usuallally gives rise to lytic bone metastases

Question 25

What are the typical lesions that renal cell carcinoma metastases to bone give rise to? What can happen on biopsy or surgery of these masses?

Answer 25

Renal cell carcinoma usually gives rise to potentially large and very vascular lytic “blow out” bony metastases which can bleed tremendously with biopsy or surgery

Question 26

What are the bones most frequently involved with metastases? Patients presenting with ref flags should be investigated at least with an intial xray. If a lesion is found on xray, what should be carried out to exclude a primary bone tumou?

Answer 26

Bones most frequently involved with metastases include the vertebra, pelvis, ribs, skull, humerus and long bones of the lower limb

If a lesion is found on xray in a patent presenting with red flag symptoms, a primary bone tumour must be excluded (by none scan and occasionally MRI)

Question 27

What simple tests are carried out to look for different bone cancer mets * Breast * Prostate * Lung * Mets to liver * Myyeloma

Answer 27

Breast - breast exam

Prostate - PR exam

Lung - CXR for a pulmonary lesion

Mets to liver - LFTs

Myeloma - plasma protein electrophoresis (showing a high level of paraprotein) and early morning urine collection for Bence Jones protein assay.

Question 28

How or fractures of impending fractures due to bone cancer treated? How is destruction of a joint treated? What must be given after surgery?

Answer 28

Fractures or impending fractures are treated with stabilisation (using long rods - intramedullary nails) If there is destruction of a joint (eg acetabulum of femoral head), joint replacement may be a better option

Surgery has a high risk of DVT and prophylaxis must be given

Question 29

Painful bone cancer lesions that are thought not to be at risk of impending fracture can be treated with what?

Answer 29

Painful lesions thought not to be at risk of impending fracture can be treated with bisphosphonates and radiotherapy (if radiosensitive).

Question 30

What is the urgent management of spinal cord compression from cancer (primary or mets) in the vertebral column? What is the usual treatment options after the initial urgent treatment has been carried out?

Answer 30

Urgent management of spinal cord compression - STEROIDS AND SCAN (Dexamethasone and MRI)

Usual treatment option - radiotherapy is the commonest and mainstay (surgery can carried out in certain scenarios)