Malignant MSK tumours

Question 1

What are the 3 main malignant MSK tumours ?

Answer 1

• Osteosarcoma
• Chondrosarcoma
• Ewings sarcoma

Question 2

Describe the epidemiology of osteosarcomas

Answer 2

• The commonest primary malignant tumour
• Usually young adults 60% occur < 25
• If in older patients usually have predisposing condition esp pagets
• Over half arise around the knee, affecting ends of long bones esp distal femur, proximal tibia and humerus

Question 3

Describe the histopathology of osteosarcomas

Answer 3

It is where you have malignant osteoblasts forming osteoid (unminerlaised organic component of bone)

spreads within the medulla, then penetrates/ partially destroys the cortex to extend beneath the periosteum and eventually into surrounding tissues

Question 4

Describe the treatment of osteosarcomas

Answer 4

1. Biopsy, CT, bone scan
2. Pre-operative chemo
3. Surgical ressection
4. Post-operative chemo

The chemo is done as there is usually early blood born metastasis often affecting the lungs

Question 5

Describe the epidemiology of chondrosarcomas

Answer 5

• Second most common primary malignant bone tumour
• Normally affects middle ages -elderly people (40-70)
• Most arise in pelvis or prox femur

Question 6

Describe the histopathology of chondrosarcomas

Answer 6

• Exhibits pure hyaline cartilage differentiation. Composed of malignant chondrocytes
• Tumour can be central (in medullary cavity) or peripheral (on the bone surface)

Question 7

Describe the treatment of chondrosarcomas

Answer 7

Wide surgical excision (chemo and radiotherapy ineffective)

Question 8

Describe the epidemiology of ewings sarcoma

Answer 8

• Highly malignant, typically affecting the metaphysis and diaphysis of long bones (femur, tibia, humerus) and pelvis
• Affects children and adolescents (5-20)

Question 9

Describe the histopathology of ewings sarcoma

Answer 9

Tumour originates in the medullary cavity, rapidly penetrates the cortex, elevates the the periosteum and forms large soft tissue mass

Question 10

Describe the treatment of ewings sarcoma

Answer 10

1. Wide surgical ressection
2. Radiotherapy
3. Neo‐adjuvant chemotherapy (given prior the surgery)
4. Post-operative chemo

Question 11

Describe what myeloma is and state the 2 different types of it

Answer 11

Myeloma is the malignant proliferation of plasma cells in bone marrow. It can present as a solitary lesion (known as a plasmacytoma) or with multiple osteolytic lesions throughout the skeleton (known as multiple myeloma).

Question 12

Describe the typical presenting features of myeloma

Answer 12

• Patients are typically aged 45‐65
• With multiple myeloma have weakness, back pain, bone pain, fatigue, and weight loss and may have marrow suppression resulting in anaemia and recurrent infection.
• Patients may present with pathologic fracture.

Question 13

How is myeloma diagnosed ?

Answer 13

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

Question 14

What additional investigation is required for pts with myeloma and why ?

Answer 14

A skeletal survey of xrays is required - because the lytic bone lesions which can be present may not be detected on a bone scan

Question 15

What is the tx of multiple myeloma and plasmocytoma ?

Answer 15

Treatment of a solitary plasmacytoma is by radiotherapy whilst treatment of multiple myeloma is by chemotherapy

Question 16

Lymphoma (a cancer of round cells of the lymphocytic system / macrophages) can occur as a primary bone tumour (as Non Hodgkins Lymphoma) from the marrow or lymphoma (any type) can metastasize to bone (in 20% of cases).

What is the treatment of primary lymphoma of bone or metastatic lymphoma affecting bone ?

Answer 16

• Primary lymphoma of bone tends to affect the pelvis or femur and treatment is with surgical resection.
• With metastatic lymphoma lymphadenopathy or splenomegaly may be present and treatment is chemotherapy and radiotherapy

Question 17

What are Fibrosarcoma and Malignant Fibrous Histiocytoma & who do they present in ?

Answer 17

They are fibrous malignant primary bone tumours which tend to occur in abnormal bone (bone infarct, fibrous dysplasia, post irradiation, Paget’s disease)

Question 18

What are the common malignant tumours which metastasise to bone & what is there radiological appearance ?

Answer 18

• Thyroid
• Breast - can be blastic (sclerotic) or lytic
• Lung - lytic bony metastases
• Renal - large and very vascular lytic “blow out” bony metastases which can bleed tremendously with biopsy or surgery.
• Prostate - produces sclerotic metastases

Question 19

What are the investigations which should be done in someone with a potential bone tumour ?

Answer 19

1. Any pain with “red flags” or suspected pathological fracture 1st line = xray
2. 2nd line if lesion seen = bone scan

If there are multiple metastases or the lesion is suspected to be metastatic, the primary tumour should be sought:

• Examination may include breast exam or PR exam.
• CXR may detect a pulmonary lesion.
• Blood tests include serum calcium (for hypercalcaemia), LFTs (to look for liver mets), plasma protein electrophoresis (for myeloma), full blood count and U&E.

Question 20

How should fractures or impending fractures caused by metastatic bone tumours be treated?

Answer 20

stabilization using long rods (intramedullary nails) whilst if there is destruction of a joint (eg acetabulum or femoral head) the joint replacement may be a better option

Question 21

How should painful metastatic bone tumours be treated?

Answer 21

• Painful lesions thought not to be at risk of impending fracture can be treated with bisphosphonates and radiotherapy (if radiosensitive).
• Spinal cord compression can occur with advanced spinal metastases and can be improved with radiotherapy or surgical decompression (anterior or posterior).

Question 22

Match the bone tumour to the description:

1. Affects the young <20, benign tumour, esp affects the femur, humerus and tibia
2. Benign but locally aggressive, people aged 25-40, affects epiphysis of long bones often around the knee
3. Benign, esp affects the hands and feet
4. Benign but locally aggressive, affects metaphysis or diaphysis of long bones and spine
5. Malignant, normally affecting middle aged - elderly (40-70), most arise in axial skeleton, pelvis, femur, humerus and ribs
6. Benign, usually children and young adults (10-30), occurs in shafts of long bones (femur tibia, hands/feet and axial skeleton)
7. Malignant, commonest primary malignant bone tumour, usually affects young adults <25, if in older patient s often associated with pagets, over half arise around the knee
8. Benign, usually 10-20yrs old, epiphysis of long bones
9. Benign but locally aggressive, occurs in adults 40+, affects sacrum, skull base and spine
10. Malignant, typically affects long bones (femur, tibia, humerus) and pelvis, most common in children and adolescents (5-20)

Osteochondroma, chondroma/enchondroma, osteoid osteoma, chondroblastoma, giant cell tumour, osteoblastoma, chorodoma, osteosarcoma, chondrosacroma, ewings sarcoma

Answer 22

Match the bone tumour to the description:

1. Affects the young <20, benign tumour, esp affects the femur, humerus and tibia - osteochondroma
2. Benign but locally aggressive, people aged 25-40, affects epiphysis of long bones often around the knee - giant cell tumour
3. Benign, esp affects the hands and feet - chondroma/enchondroma
4. Benign but locally aggressive, affects metaphysis or diaphysis of long bones and spine - osteoblastoma
5. Malignant, normally affecting middle aged - elderly (40-70), most arise in axial skeleton, pelvis, femur, humerus and ribs - chondrosarcoma
6. Benign, usually children and young adults (10-30), occurs in shafts of long bones (femur tibia, hands/feet and axial skeleton) - osteoid osteoma
7. Malignant, commonest primary malignant bone tumour, usually affects young adults <25, if in older patient s often associated with pagets, over half arise around the knee - osteosarcoma
8. Benign, usually 10-20yrs old, epiphysis of long bones - chondroblastoma
9. Benign but locally aggressive, occurs in adults 40+, affects sacrum, skull base and spine - chordoma
10. Malignant, typically affects long bones (femur, tibia, humerus) and pelvis, most common in children and adolescents (5-20) - ewings sarcoma