Musculoskeletal Neoplasms and Metastatic Disease

Question 1

What is the metaphysis?

Answer 1

The area between the diaphysis (shaft) and the epiphysis where the bone widens

Question 2

What is the inside of bone and outside layer of bone called?

Answer 2

Compact bone = cortical bone = Outer layer of bone

Spongy bone = Trabecular bone = Cancellous bone = Inside layer of bone

Spongy bone + bone marrow = medullary cavity

Question 3

What is lamellar bone and what is woven bone?

Answer 3

Lamellar bone = mature bone

Woven bone = osteoid = immature/new bone (can be produced by tumours)

Question 4

What are the most common bone tumours?

Answer 4

Metastatic tumours from other parts of the body

Question 5

What are the classes of bone tumours (classification by aetiology)?

Answer 5

Metastatic disease

Haematolymphoid malignancies (Plasma cell myeloma and Primary bone lymphoma)

Primary bone tumours (rare in comparison to metastases and haematolymphoid malignancies)

Question 6

Which cancers most commonly metastasize to bone? (in order of incidence)

Answer 6

Lung, breast, prostate, colorectal adenocarcinoma

Thyroid adenocarcinoma

Renal Cell Carcinoma

Malignant melanoma

Question 7

What are the types of bone metastases?

Answer 7

Osteolytic metastases: Bone is destroyed by tumour cells these are called osteolytic metastases. Cytokines stimulate osteoclastic bone resorption.

Osteoblastic metastases: Cytokines stimulate osteoblastic activity and new bone

Question 8

Which cancers typically result in osteoblastic metastases?

Answer 8

Prostate and breast carcinomas

Question 9

What are the most common types of haematolymphoid malignancies?

Answer 9

Plasma cell (multiple) myeloma

Primary bone lymphoma (haematology)

Question 10

What is plasma cell myeloma?

Answer 10

Previously called multiple myeloma, bone marrow-based malignant neoplasm of plasma cells. Forms multiple tumours throughout skeletal system

Question 11

What is the incidence of plasma cell myeloma?

Answer 11

Most common primary malignancy of bone. (usually in >50yo

Question 12

What are the clinical symptoms of plasma cell myeloma?

Answer 12

Bone pain, pathological fracture (tumours in bone)

Hypercalcaemia (osteoclastic bone destruction)

Monoclonal immunoglobulin in serum and urine (clonal proliferation of plasma cells)

Renal failure (paraprotein deposits in kidney)

Susceptibility to infection (abnormal immunoglobulin)

Anaemia (Chronic disease)

Question 13

What is an M protein/paraprotein?

Answer 13

Protein produced by abnormal plasma cells that have proliferated.

Question 14

How are bone tumours identified?

Answer 14

Their clinicopathological features are relatively constant:

Age of patient

Bone and area affected

Radiological and pathological features (multidisciplinary bone tumour meeting)

Question 15

How are bone tumours managed?

Answer 15

Several disciplines are involved because it can affect relatively young people.

Question 16

What are the types of tumours and how are they further divided?

Answer 16

Bone forming (eg osteosarcoma)

Cartilaginous

Fibro-osseus

Fibrous/fibrohistiocytic

Giant cell rich

Cystic lesions

Miscellanious

These tumours are further divided into benign and malignant categories

Question 17

What type of tumour is the osteosarcoma?

Answer 17

Bone forming malignant mesenchymal neoplasm (sacoma) producing bone matrix.

Question 18

How common is osteosarcoma?

Answer 18

Most common primary malignant tumour of bone and most commonly affects children.

Males are slightly more commonly affected and there is a bimodal age distribution (10 - 20s and then >20 years old)

Question 19

What are the risk factors for primary bone cancer?

Answer 19

Adolescents

Majority idiopathic

Hereditary retinoblastoma

Li-Fraumeni syndrome (p53 mutation)

Ionising radiation

Question 20

What are the risk factors for secondary bone cancer?

Answer 20

Older adults

Underlying benign bone disease: Paget’s disease, benign bone tumours, chronic osteomyelitis

Question 21

What are the clinical symptoms of osteosarcoma?

Answer 21

Nocturnal local bone pain

Palpable mass

Pathological fracture

Constitutional symptoms (fever, anorexia, weight loss, metastatic disease)

Destructive mass in medullary cavity invading through cortex that can be identified using Codman’s triangle on x-ray or sunburst pattern.

Question 22

What is the prognosis for osteosarcoma?

Answer 22

80% 5 year survival rate in localised disease

30% 5 year survival rate in metastatic disease

Question 23

What do osteosarcomas look like on histology?

Answer 23

Malignant tumour cells produce osteoid matrix in a delicate pericellular lacelike pattern. This is most prominent in osteoblastic variant.

Question 24

What is an osteoid osteoma?

Answer 24

A benign bone-forming tumour.

Question 25

How do osteoid osteoma present clinically?

Answer 25

Presents as nocturnal pain that is responsive to NSAIDs

Question 26

Where are osteoid osteomas most commonly seen?

Answer 26

Affects people from 5 - 20 years of age and males twice as often as females. It is seen on the long bones most often within the cortex.

Question 27

How common is the osteoid osteoma?

Answer 27

It makes up 15% of all primary benign bone tumours

Question 28

What does osteoid osteoma look like on histology and macroscopically?

Answer 28

It is a small circumscribed cortical-based lesion Trabeculae of woven bone Plump osteoblastic rimming

Question 29

What is an enchondroma?

Answer 29

Benign intramedullary cartilaginous neoplasm

Question 30

Where are enchondromas commonly seen?

Answer 30

In small tubular bones of hands and feet (phalanges) > long bones

Question 31

How common are enchondromas?

Answer 31

25% of primary benign bone tumours

Question 32

Who is most commonly affected by enchondromas?

Answer 32

Males and females equally in their 20s and 30s

Question 33

What are the risk factors for enchondroma?

Answer 33

Multiple lesions are formed in Ollier's syndrome

Question 34

What is the clinical presentation of enchondroma?

Answer 34

Asymptomatic; it is often an incidental radiological finding. Can cause pain with pathological fracture in some cases.

Question 35

What is the prognosis of enchondromas?

Answer 35

Benign and can be treated with local curettage.

Question 36

What does enchondroma look like histologically and macroscopically?

Answer 36

Radiologically: Circumscribed cartilaginous lesion Expanding medullary cavity of tubular bones Histologically: Nodules of hyaline cartilage Sharp interface with trabecular bone

Question 37

What is an osteochondroma?

Answer 37

Benign pedunculated tumour of bone with cartilage cap overlying bony stalk Commonly called exostosis

Question 38

How common are osteochondromas? Who are they most commonly seen in?

Answer 38

Most common benign bone tumours (50%) Seen more in males than females that are 10 - 20 years of age.

Question 39

Which part of the bone do osteochondromas most commonly affect?

Answer 39

Metaphyseal surface of long bones

Question 40

What are the risk factors for ostechondroma?

Answer 40

Most common one is multiple hereditary exostosis which is an autosomal dominant condition.

Question 41

What is the clinical presentation of osteochondroma?

Answer 41

Usually asymptomatic and seen on radiology indidentally (unless impinging on a nerve or if there is fracture of stalk)

Question 42

What is the prognosis of osteochondroma like?

Answer 42

Benign and can be treated with conservative management Symptomatic cases cured with simple excision

Question 43

What does an osteochondroma look like radiologically and histologically?

Answer 43

Radiologically: Pedunculated (mushroom-like) lesion arsing from metaphysis that points away from joint space Stalk is continuous with medullary cavity Histologically: Cartilage cap (neoplastic part of the tumour) Merges with underlying bony stalk through endochondral ossification

Question 44

What is fibrous dysplasia?

Answer 44

A benign fibro-osseus tumour of bone.

Question 45

Who most commonly gets fibrous dysplasia?

Answer 45

7% of primary benign tumours Early to mid adulthood and affects axial skeleton more often than long bones.

Question 46

What are the risk factors for fibrous dysplasia?

Answer 46

Usually it is monoastotic but can also be polyastotic (McCune-Albright syndrome) It is non-inherited

Question 47

How does fibrous dysplasia present clinically?

Answer 47

Most are incidental radiological findings.

Question 48

What does fibrous dysplasia look like radiologically and histologically?

Answer 48

Radiologically: Well-defined ground glass opacity within medullary cavity Varus deformity in femur (shepherd's crook) Histologically: Fibro-osseus tumour Curvilinear arrays of woven bone (resembles chinese writing) Fibrous stroma with bland spindle cells.

Question 49

What is Ewing sarcoma?

Answer 49

A highly malignant small, round, blue cell tumour. It is a primitive ectodermal tumour (PNET)

Question 50

How common is ewing sarcoma and who is it most common in?

Answer 50

It makes up 10% of primary malignant bone tumours, affects children from 10 - 15 years of age and affects males more than females. Primarily affects the long bones and pelvis

Question 51

How does ewing sarcoma typically present?

Answer 51

Painfully enlarging mass It is usually detected only after it becomes metastatic

Question 52

What is the prognosis of ewing sarcoma?

Answer 52

5 year survival rate is 75% Long term cure only in 50%

Question 53

How is ewing sarcoma diagnosed?

Answer 53

Prototypical small round blue cell tumour with rosettes on histology (due to cells being almost completely nuclei) EWSR1-FLI1 t(11;22) translocation on FISH Diffuse CD99 staining immunohistochemistry

Question 54

What is a sarcoma?

Answer 54

A malignant soft tissue tumour. (very rare)

Question 55

How do soft-tissue tumours present clinically?

Answer 55

Palpable mass for extremity tumours Abdominal distension for abdominal/retroperitoneal tumours Things that increase suspicion for sarcomas: Tumour size >5cm or enlarging mass Deep-seated (deep to fascia/intramuscular) Painful Multiple lesions

Question 56

How are soft tissue tumours classified?

Answer 56

WHO classification: >140 different subtypes Histological classification: Line of differentiation Mature mesenchymal tissue which the tumour most closely resembles