Musculoskeletal Tumour Society Staging System
Stage 1 Benign inactive
Stage 2 Benign active
Stage 3 Benign aggressive
Stage I Low grade malignant
Stage II High grade malignant
Stage III Metastases to any site
Purpose
- guide prognosis
- guide surgical management
- guide adjunctive therapies
Compartments
Definition
A compartment is an anatomically confining space
- will resist tumour spread beyond its boundaries
Intra-compartmental (4)
- intra-osseous
- intra fascial compartments
- superficial to deep fascia
- par-osseous
Extra-compartmental
- extension beyond above
- pelvis
- popliteal fossa
- axilla
- cubital fossa
Benign
Latent / Inactive
Non-ossifying fibroma
- benign, intracapsular, no metastatic potential
- typical clinical course is unchanging or self-limiting
- tendency to self healing
Active
ABC
- characteristic is progressive growth
- benign, intracapsular, no metastatic
- X-ray and clinical appearance suggests active but contained growth
- without extracapsular penetration
5-10% local recurrence with curettage
- respond well to wide excision
Aggressive
GCT
- locally aggressive but no metastatic potential
- benign, extracapsular but intra-compartmental
- X-ray and clinically characterised by extracapsular penetration & destructive growth
10-20% recurrence after marginal excision
- may even recur after wide excision
- best treatment by excision with cuff of tissue
Malignant
1A Low Grade Intra-compartmental
1B Low Grade Extra-compartmental
2A High Grade Intra-compartmental
2B High Grade Extra-compartmental
3 Metastasis
Low grade
- low metastatic potential
- parosteal OS
Treatment is surgery alone
- don't require systemic treatment
- tumour nodules in reactive zone but not beyond
- wide excision
High grade
- grow rapidly & metastasise early
- tumour nodules beyond reactive zone
- classis central OS
Treatment is surgery & systemic treatment