Orthopaedic Oncology

Question 1

Types of sarcomas

Answer 1

Tumours of connective tissue
-Soft tissue tumours
-Primary bone tumours (any tissue of mesenchymal origin)
-Metastatic bone disease

Question 2

Sarcoma and metastasis pathophysiology

Answer 2

Initial growth (centrifugally, displace tissues), local mass effect (compression), metastasis (lungs)

1. ‘Seed and Soil’: carcinomas may metastasise to any bone, including the spinal column
2. Localised metastasis growth within bone: ‘stretches’ the bone, resulting in pain
3. Erodes bone, resulting in spontaneous fracture. This is through:
   =Direct bony destruction from the tumour
   =The tumour stimulating osteoclasts to resorb bone(osteolytic)
   =The deposition of new, but disorganised bone (osteoblastic)

SOFT TISSUES

Question 3

Presentation of soft tissue tumour

Answer 3

-Lump
-Local compression of structures (nerves and blood vessels)

Question 4

Presentation of bone tumour

Answer 4

-Lump if it erodes bone or bone remodels
-Pain
-Fracture

Question 5

Presentation of metastatic bone disease

Answer 5

-Pain
-Fracture

Question 6

Examining a lump description

Answer 6

-Describe from superficial to deep
-Location
-Appearance of overlying skin (colour, texture)
-Size and shape
-Borders (well-defined or poorly defined)
-Surface (smooth, rough)
-Texture (fluid, fluctuance, nodular, mixed)
-Mobility
-Anatomical layer

Question 7

Investigating tumours

Answer 7

-History and exam
-Imaging
-Histopathology
=Biopsy (diagnostic, image-guided)
-Guided my MDT discussion

Question 8

Describe imaging in bone tumours

Answer 8

-Soft tissue masses:
=USS < 5cm in size and superficial
=MRI for all other masses
-Primary bone tumours:
=Plain XR of the whole bone
= + MRI
-Metastasis:
=Plain XR
-CT-Chest (sarcomas) or CT-CAP (metastasis)

Question 9

Describing a radiograph in bone tumours

Answer 9

Describe the lesion broadly, then move from the centre of the lesion outwards

-Lesion:
=Lytic (bite out/black) / sclerotic (white)/ mixed
=Location
=Size and shape

-Centre moving outwards:
=Contents – bony / cartilaginous / fluid
=Borders – are they well-defined or poorly-defined
=Cortex – eroded / thin / expansile
=Periosteum
=Soft tissue expansion

Question 10

Types of soft tissue tumours

Answer 10

-Benign
=Lipoma (2100 per million)
=Giant cell tumour of tendon sheath (2 per million)

-Malignant
=Liposarcoma (2.5 per million)
=Atypical lipomatous tumour (1.25 per million)
=Rhabdomyosarcoma (1 per million)

Question 11

Describe lipoma

Answer 11

-Benign tumour of mature fat cells
-Slow growing, painless, subcutaneous mass, which can appear anywhere
-Usually superficial, but occasionally deep / intra-muscular
-Smooth, well-circumscribed, rubbery, mobile masses
-Inv: USS if superficial; MRI if deep or >5cm in size
-Rx: Excision if symptomatic, >5cm, or atypical features
-No risk of malignant transformation

Question 12

Describe liposarcoma

Answer 12

-Malignant tumours of mature fat cells
-Rapidly growing subcutaneous mass, which is painful in ~1/3rd of patients
-Extremities and the retroperitoneum
-Well-circumscribed, nodular mass. Usually mobile. May compress local neurovascular structures
-Inv: MRI and biopsy
-Rx: Surgical excision +/- chemoRT

Question 13

Common primary bone tumours

Answer 13

-Benign
=Aneurysmal bone cyst (14 per million) =Enchondroma (10 per million)
=Giant cell tumour of bone (1.7 per million)

-Malignant
=Osteosarcoma (3.1 per million)
=Ewing sarcoma (2.9 per million)
=Chondrosarcoma (2 per million

Question 14

Describe osteosarcoma

Answer 14

-Very rare
-Malignant mesenchymal tumour that produces osteoid
-Epidemiology: 90% are adolescents and young adults (second small peak >60 y/o)
-Location: distal femur, proximal tibia, and proximal humerus (all rapidly growing areas of bone)
-Inv: XR, MRI, biopsy, CT-chest (for pulmonary mets)
-Rx: curative intent
=(Neo)adjuvant chemotherapy
=Radical surgical excision, with limb preservation and reconstruction (rather than amputation, where possible)

Question 15

Describe Ewing sarcoma

Answer 15

-Very rare
-Malignant tumour of uncertain origin. Associated with agene translocation (typically t(11:22))
-Epidemiology: Mainly adolescents and young adults
-Location: Femur, pelvis, ribs, and humerus most common
-Inv: XR, MRI, biopsy, CT-chest (for pulmonary mets)
-Rx: curative intent
= (Neo)adjuvant chemotherapy
=Radical surgical excision, with limb preservation and reconstruction (rather than amputation, where possible)
=Radiotherapy also commonly used

Question 16

Describe chondrosarcoma

Answer 16

-Very rare
-Malignant mesenchymal tumour that produces cartilaginous matrix
-Epidemiology: 5th – 8th decades of life
-Location: Pelvis, hip, and humerus are the most common
-Inv: XR, MRI, biopsy, CT-chest (for pulmonary mets)
-Rx: curative intent
=Chemoradiotherapy has little role
=Radical surgical excision, with limb preservation and reconstruction (rather than amputation, where possible)

Question 17

Describe metastatic bone disease

Answer 17

-Very common sequelae of systemic cancer
-Presents as bone pain +/- fracture
-A common complication of several cancers
=Kidney
=Thyroid
=Lung
=Prostate
=Breast

Question 18

Risk assessment of pathological fractures

Answer 18

Risk of fracture predicted by the Mirel score
=>8 = prophylactic fixation to prevent fracture

-Site upper/ lower/ peritro-chanteric
-Pain: mild, moderate, functional
-Lesion: blastic, mixed, lytic
-Lesion size/ diameter: <1/3, 2-3

Question 19

Management of pathological fractures

Answer 19

-Palliative in almost all cases
-Stabilisation (with internal fixation)or joint replacement, depending on metastasis location within the bone