Malignancy

Question 1

Name 5 benign bone tumours/disorders?

Answer 1

• osteochondroma
• osteoid osteoma
• enchondroma (more common in young adults)
• bone cysts (more common in children)
• fibrous dysplasia

Question 2

Name the 3 primary malignant bone tumours?

Answer 2

• osteosarcoma
• Ewing’s sarcoma
• chondrosarcoma

Question 3

Name 6 tumours that are most likely to metastasise to bone.

Answer 3

• breast
• lung
• prostate
• renal
• thyroid
• bowel

Question 4

Name 3 haemopoietic diseases?

Answer 4

• myeloma
• leukaemia
• lymphoma

Question 5

What 3 general conditions can present with a bone lesion?

Answer 5

• infection of the bone
• metabolic bone disease
• cancer of the bone

Question 6

Where do secondary bone metastases tend to be found?

Answer 6

• in the central skeleton and proximal limbs (hips and shoulders)

Question 7

Lytic lesion on x-ray (suggestive of malignancy)…

Answer 7

Question 8

Fibrous dysplasia (x-ray, what is it)…

Answer 8

• x-ray: ‘ground-glass’ appearance
• fibrous dysplasia: not strictly a bone tumour, caused by a developmental abnormality of bone with numerous fibrous proliferations

Question 9

What blood tests should be done in suspected malignancy of the bone?

Answer 9

• FBC: may show anaemia of chronic disease
• LFTs: to see if liver metastases are present
• Calcium profile: elevated in generalised malignancy
• ALP: elevated in Pagets
• CRP/ESR: elevated in infection or malignancy
• (Prostate-specific antigen (PSA): elevated in prostate malignancy)
• (Carcinoembryonic antigen (CEA): elevated in bowel carcinoma)

Question 10

Apart from x-rays and blood tests, what other investigations can be done if malignancy is suspected?

Answer 10

• Isotope bone scan: both malignancy and infection will show as hot
• CT: used to confirm osteoid osteoma
• MRI: can detect early metastatic lesions (before x-rays), also used to see the extent of tumours
• Biopsy: provides good detail of the tumour

Question 11

What is an enchondroma?

Answer 11

• a benign bone lesion of cartilaginous origin
• enchondromas develop from aberrant cartilage (chondroma) left within the bone (‘en’)
• usually found within the metaphysis of long bones (femur or humerus)

Question 12

Enchondroma and osteochondroma diagram…

Answer 12

Question 13

What is an osteochondroma?

Answer 13

• the most common benign bone lesion
• develops from aberrant cartilage remaining on the surface of the cortex

Question 14

What is an osteoid osteoma?

Answer 14

• painful, self-limiting benign bone lesion
• caused by an accumulation of osteoblasts located in the cortex of bone

Question 15

X-ray and CT image of osteoid osteoma…

Answer 15

Question 16

What is an osteosarcoma?

Answer 16

• Paget disease or radiation can predispose
• the tumour is highly malignant and secretes osteoid
• local spread occurs quickly, destroying the cortex, but it may also metastasise
• (most common in knee, proximal humerus, femur)

Question 17

What is the treatment for an osteosarcoma and what is the treatment for a chondrosarcoma?

Answer 17

• BOTH: MDT approach important
• Osteosarcoma: chemotherapy, potentially amputation
• Chondrosarcoma: wide excision sometimes, potentially amputation

Question 18

What is a chondrosarcoma?

Answer 18

• occurs in older patients (>40yrs)
• symptoms: pain and a lump
• many arise from previous chondromas that have undergone malignant change
• x-ray: ‘fluffy popcorn’ calcification

Question 19

Mechanism of long-bone metastasis…

Answer 19

Question 20

What is the conservative management for secondary bone tumours?

Answer 20

• Analgesia and splinting
• radiotherapy / chemotherapy
• IV bisphosphonates: to inhibit osteoclastic resorption of bone

Question 21

What is the surgical management for secondary bone tumours?

Answer 21

• intramedullary fixation of long bones for fracture or impending fracture
• joint arthroplasty
• spinal cord decompression and stabilisation for acute cord compression

Question 22

What is the prognosis for secondary bone tumours?

Answer 22

• prognosis depends on the primary tumour

Question 23

What is lymphoma?

Answer 23

• Lymphoma is a malignant haematopoietic tumour, usually occurring secondarily in bone
• note: primary bone lymphoma has better prognosis

Question 24

What is haematopoiesis?

Answer 24

• the process through which the body manufactures blood cells
• it occurs within the hematopoietic system (includes organs and tissues such as the bone marrow, liver, and spleen)

Question 25

What investigations should be done for suspected lymphoma?

Answer 25

• X-ray: shows a long lesion with mottled bony destruction
• Isotope bone scan: excludes further lesions
• Biopsy: confirms diagnosis
• (most commonly affects the pelvis, spine, and ribs)

Question 26

What is myeloma?

Answer 26

• a tumour, lesions are due to a plasma cell malignancy
• usually found in spine, ribs, or clavicle
• note: poor prognosis

Question 27

What investigations should be done for suspected myeloma?

Answer 27

• X-ray: shows classic punched-out lytic lesions
• ESR: high
• Urinary analysis: Bence-Jones proteins (light-chain proteins)

Question 28

What is leukaemia?

Answer 28

• a malignancy of white blood cells
• most common malignancy of childhood
• 1/3 of patients have bone pain
• Leukaemia can present with an acutely hot swollen joint (very similar to septic arthritis)

Question 29

Ewing’s sarcoma (symptoms, investigations, x-ray)…

Answer 29

• occurs in adolescents (rare)
• symptoms: pain, eythema, mass along long bone diaphysis, systemic symptoms (fever, anaemia)
• investigations: raised ESR and WCC, x-ray
• x-ray shows onion skin periosteal reaction
• (histology: small-cell sarcoma)

Question 30

Osteosarcoma (symptoms, x-ray)…

Answer 30

• most common primary bone malignancy, occurs mainly in adolescent males
• symptoms: warm, painful swelling, most commonly at knee
• x-ray: periosteal reaction with codman’s triangle and a sunburst appearance