Steps
1. Establish a differential
2. Stage locally and systemically
3. Biopsy
4. Definitive Treatment
1. Establish a Differential
Lesion detected on X-ray
Questions
- what do you think it is?
- is it benign (latent, active, agressive)?
- is it malignant (primary or secondary)?
Enneking's four questions
1. Where is the tumour?
Flat bone / long bone
Epiphysis / metaphysis / diaphysis
Medullary canal / cortex
Eccentric in bone
2. What is it doing to the bone?
Expansion
Cortical erosion / breakthrough
Fracture
Permeative margins
Wide / narrow zone of transition
- narrow / can draw edge with a pen / good sign
- wide / infiltrative / bad sign
The best indication of the aggressiveness of a tumour is the transition zone or margin that surrounds the bone
3. What is the bone doing to it?
Periosteal reaction
- Codman Triangle / Sunburst / Onion Skinning
Reactive rim
- Sclerotic = Slow growing
- Ill defined = Fast growing
Margin
1. Moth eaten / permeative / ill defined / wide zone of transition / cortical or cancellous
2. Well circumscribed / narrow zone of transition / sclerotic rim
4. Are there any clues to its histological diagnosis?
Bone formation / Calcification
Soft tissue component
Radiolucent / ground glass
Matrix Osteoid / Chondroid / Myxoid / Collagen
DDx Lucent lesions
FOGMACHINES
Fibrous dysplasia
Osteoid Osteoma / Osteoblastoma / Osteosarcoma
Giant cell tumour
Metastasis / myeloma
ABC
Enchondroma / Chondroblastoma / Chondrosarcoma
Hemangioma / HPTH
Infection / Intraosseous ganglion or lipoma / Infarct
Non Ossifying Fibroma / Neurofibroma
EG
Simple bone cyst / Synovial Proliferation
Patient factors
Age
- consider primary bone tumour < age 40
- consider metastasis > age 40
- consider EG < age 10
History
Malignant pain
- night time, severe, increasing
Trauma
Examination
Soft tissue mass = Aggressive lesion
Inflammation = Infection / Ewing's
Pathology tests
Serum electrophoresis / Urine Bence Jones (Multiple Myeloma)
PSA - prostatic cancer
ESR - non specific (increased in infection / Ewing's / MM / lymphoma / metastasis)
ALP - increased in Osteosarcoma & Paget's
Calcium / PTH - think of hyperparathyroidism
Other Tests
Mammogram / Thyroid Ultrasound - metastasis
CT Chest / abdomen / pelvis - RCC, lung cancer, bowel cancer
Old X-rays
Consider observation if lesion unchanged from at least 2 years ago
2. Stage Locally and Systemically
Purpose
- accurately define the extent of the disease
- prior to proceeding with biopsy and definitive treatment
Local / Cross sectional imaging
CT
Best for assessing mineralisation & bony details
- benign bone tumours
- violation of cortex
- matrix mineralisation
- shows areas that plain X-ray visualise poorly i.e. Spine / Pelvis
MRI
Best for assessing soft tissue component
Assess
1. ST tumours
2. Cortical breakthrough / T2
3. Soft tissue extension / T2
4. Marrow involvement / intramedullary spread
- T1 with fat suppression
5. Relationship to NV bundle / T2
6. Joint & Epiphyseal involvement
7. Infection - rim enhancement on gadolinium
Advantage
- guides extent of treatment
- > 5cm margin on MRI / wide excision
Disadvantage
- may be oversensitive
- oedema vs tumour
Distant
Bone scan
Determines if lesion polyostotic v monostotic
- this aids with differential diagnosis
- will identify metastasis
False negative / cold scan
- inactive benign tumours
- myeloma / EG / melanoma
CT Chest / Abdo / Pelvis
Purpose
- identify primary tumour that may have metastasised to bone
- identify liver and lung metastasis
Classify Lesion
Benign - no need for biopsy
Uncertain or malignant - need for biopsy
3. Biopsy
Aim
A. To determine whether benign or malignant
B. To determine specific cell type
C. To determine grade
See Principles of Biopsy
4. Definitive Treatment
See specific tumour articles