Following describes approach to tumours of musculoskeletal system
Classification (Enneking)
Benign Bone Tumours
Latent Grow with individual & then stop with tendency to spontaneous resolution
(Non ossifying fibroma, Lipoma)
Active Progressive growth & excision leaves reactive zone with tumour
(ABC)
Aggessive Locally aggressive but does not metastasize & has tumour extension through capsule into reactive zone
(GCT & Desmoid)
Malignant Bone Tumours
I Low Grade
II High Grade
III Metastatic
– Intracompartmental
B – Extracompartmental
Staging of Tumours
Stage tumours
Locally
Systemically
Involves
Serological investigations
FBE
ESR
CRP
LFT (esp. ALP)
Ca, PO4
Radiological investigations
Local
X-ray
CT
MRI
Systemic
Bone scan
CXR (see mets down to ~ 1cm diameter)
Chest CT (see mets down to ~ 2mm diameter)
X-ray » Ennekings four questions
1. Where is tumour?
Flat bone / Long bone
Epiphysis / Metaphysis / Diaphysis
Medullary canal / Cortex
2. What is it doing to bone?
Erosion / Expansion / Cortical breakthrough
Fracture
Transition zone
3. What is bone doing to it?
Periosteal reaction
Continuous
Interrupted
Codman Triangle
Complex
Sunburst
Multi or Single laminated
Onion Skinning
Reactive rim
Sclerotic = Slow growing
Ill-defined = Fast growing (Permeative)
4. Are there any intrinsic clues to histological diagnosis?
Bone formation / Calcification
Soft tissue component
Radiolucent / Ground glass
Matrix is intercellular material produced
May be
Osteoid
Chondroid
Myxoid
Collagen
Osteogenic sarcoma » bone production seen
Chondrosarcoma » punctate calcification seen
Fibrosarcoma » moth-eaten, permeative lesion
Blood vessel tumours » bubbly areas in bone (incl. Telangiectatic OS)
Most tumours lie in metaphysis
Epiphyseal tumours are
GCT » most likely epiphyseal tumour in adult
Chondroblastoma » most likely epiphyseal tumour in child
Chondromyxoid fibroma (soap bubble appearance like ABC)
Clear cell chondrosarcoma (epiphyseal chondrosarcoma)
(Unicameral bone cysts & ABC may appear in epiphysis)
Diaphyseal tumours are
Osteoid osteoma
Osteoblastoma
Chondrosarcoma arising from previous enchondroma
Fibrosarcoma (or other reticulum cell sarcomas)
Eosinophilic granuloma
Ewings
Primary lymphoma of bone
Intracortical tumours are
Osteofibrous dysplasia (ossifying fibroma)
Osteoid osteoma
Intracortical osteosarcoma
Adamantinoma
Worthwhile considering in Differential Diagnosis of nearly all lesions
Fibrous dysplasia
Eosinophilic granuloma
Ewings
Tuberculosis
Neoplastic ossification
Via 3 mechanisms
Primary Intramembranous Formation
Produced by
Osteosarcoma
Osteoid Osteoma & Osteoblastoma
Direct deposition of pathological woven bone
Via intramembranous ossification
Enchondral Ossification
Produced by
Osteochondroma
Enchondroma
Synovial Chondromatosis
Enchondral ossification of pathological cartilage
Reactive Bone
Occurs adjacent to neoplasm
Formed by host osteoblasts
Other Imaging
With primary bone tumours plain XR & CT often most useful in telling type of tumour
CT scan & MRI if further information required
CT Scan
Best for assessing mineralization & bony details
Shows local extent of tumour
Intraosseous
Violation of cortex & extension into soft tissue
Shows areas that plain XR visualize poorly
Spine
Pelvis
MRI Scan
All cases should probably have MRI
Determines extent of disease
Medullary extent
Reactive zone & satellite lesions
Skip lesions
MRI is excellent to determine extent of disease (reactive zone) but often very poor in diagnosing type of tumour
Eg. Myositis ossificans appears benign on plain XR but appears very aggressive with significant surrounding reactive change (oedema) on MRI
Bone Scan
Very useful for determining tumour extent (medullary extent & skip lesions)
Useful to compare with MRI which may overcall
If multiple lesions found
Consider metastases (especially adult)
Consider other causes of multiple hot spots
Tumours that are cold on bone scan “MAGEE”
Myeloma
Aggressive tumours
GCT
EG
Ewings
Non-Tumourous conditions that may mimic Tumours
Osteomyelitis (esp Brodie’s abscess)
Eosinophilic granuloma
Subchondral degenerative cyst
Intraosseous ganglions
Metabolic Disease
Paget’s
Osteitis fibrosa cystica & Brown tumour
Post-trauma
Stress fracture
Myositis ossificans
Lab Findings
IgG in multiple myeloma
PSA in prostatic cancer
ESR
Nonspecific
Increased in infection
Significant elevation in Ewing’s, MM, lymphoma
Moderately elevated in metastases
Otherwise usually normal
ALP
Increased in Osteosarcoma & Paget’s
Biopsy
Principle is take adequate specimen without jeopardizing future operations
Prerequisites
- Performed by surgeon who accepts responsibility for complete surgical management of patient
- At site that can be excised en bloc at subsequent surgery
- Tourniquet
- Longitudinal incision
- Traverse within anatomical compartment
- Cut directly to tumour – do not undermine skin edges
- Periphery of tumour most useful – centre may be necrotic
- Confirm representative sample with frozen section
- Haemostasis with tourniquet down
- Closure in layers to minimise tumour spill
- Drain used & in line with incision (can be excised en bloc with tumour)
- Closed needle Bx 97% accurate, but dependent on sampling
Resection Margins
Intralesional Tumour removed in piecemeal fashion within lesion with high potential for residual disease – Benign lesions only
Marginal Traverse pseudocapsule & reactive zone is breached hence potential for leaving Satellite Lesions is high – Benign lesions only
Wide resection Intracompartmental & passes through normal tissue about entire 3D surface of lesion usually complete resection but intracompartmental Skip Lesion can be left behind – IA & IIA lesions only
Prof Peter Choong (St Vincents, Melbourne) – 3cm clearance in longitudinal plane, one anatomical margin in transverse plane
Radical resection Resection of all compartments involved with tumour – results in complete resection of lesion & any intracompartmental skip lesions
Careful imaging to ensure no skip lesions can ensure limb salvage with wide resection is equivalent to radical resection
Amputation can represent any of these resections depending on plane that passes through
Not necessarily adequate operation but method of achieving specific margin
Skip Lesions
These are lesions that represent local bony metastasis within compartment
Differs from satellite lesions as they lie outside reactive zone (zone of oedema on MRI)
Most common in high grade sarcomas
Develop through embolisation within marrow sinusoids
Age Prediliction for Tumours
1-5 Years
Osteomyelitis
Metastatic neuroblastoma
Leukaemia
Eosinophilic granuloma
Unicameral bone cyst
6-18 years
Unicameral bone cyst
ABC
Non ossifying fibroma
Ewings
Osteomyelitis
Osteosarcoma
Enchondroma
Chondroblastoma
Chondromyxoid fibroma
Osteoblastoma
Fibrous dysplasia
19-40 years
Ewings
GCT
Osteosarcoma (rare)
> 40 years
Metastatic disease
Multiple Myeloma
Chondrosarcoma
MFH
Tumours more prevalent in females
Most tumours are more common in males or have equal sex distribution
Exceptions are
Ganglions 3:1
Monostotic fibrous dysplasia 1.3:1
Giant cell tumour 1.5:1
Parosteal osteosarcoma 1.5:1
Desmoid tumours (aggressive fibromatosis)
Tumours & tumour-like conditions found in bone (Bullough text)
Bone-forming
Reactive or Post-traumatic
Reactive periostitis (parosteal fasciitis)
Subungual exostosis
Bizarre parosteal osteochondromatous proliferation (BPOP, Nora’s lesion)
Developmental or Hamartomatous
Bone island (solitary exostosis)
Osteopoikilosis
Osteopathia striata (Voorhaeve’s disease)
Melorheostosis
Benign
Surface osteomas
Osteoid osteoma
Osteoblastoma
Malignant
Osteosarcoma (osteogenic sarcoma)
Cartilage-forming
Reactive or Post-traumatic
Reactive periostitis }
Subungual exostosis } with cartilage (rather than bone) predominating
BPOP }
Developmental or Hamartomatous
Osteochondroma (osteocartilaginous exostosis)
Multiple osteochondromas (diaphyseal aclasia, hereditary multiple osteocartilaginous exostosis)
Enchondromatosis (Ollier’s disease)
Dysplasia epiphysealis hemimelica (Trevor’s disease)
Benign
Enchondroma
Juxtacortical chondroma (periosteal chondroma)
Chondroblastoma
Chondromyxoid fibroma
Fibromyxoma
Malignant
Chondrosarcoma
Chordoma
Fiber-forming
Reactive or Post-traumatic
Periosteal “desmoid”
Developmental or Hamartomatous
Fibrous cortical defect (non-ossifying fibroma, benign fibrous histiocytoma)
Fibrous dysplasia
Benign
Osteofibrous dysplasia
Desmoid
Desmoplastic fibroma
Malignant
Fibrosarcoma
MFH
Adamantinoma of long bones
Non-matrix-producing
Reactive or Post-traumatic
Epidermoid inclusion cyst
Ganglion cyst of bone
Unicameral bone cyst (simple bone cyst)
Aneurysmal bone cyst
Solid aneurysmal bone cyst (giant-cell reparative granuloma)
Developmental or Hamartomatous
Haemangioma/ lympangioma
Haemangiomatosis/ lympangiomatosis
Benign
Eosinophilic granuloma
Systemic mastocytosis
Giant-cell tumour
Lipoma (of bone)
Malignant
Ewings sarcoma
Lymphoma
Leukemia
Multiple myeloma
Solitary myeloma
Malignant blood-vessel tumours
Blood Vessel
Benign
Haemangioma
Lymphangioma
Malignant
Haemangioendothelioma
Angiosarcoma
Haemangiopericytoma
Metastatic lesions
Breast }
Prostate } 80%
Lung }
Thyroid
Bowel
Kidney
Other Tumour Like Conditions
Myositis ossificans
Brown tumour (occurring in osteitis fibrosa cystica from hyperparathyroidism)
Tumours within marrow
Ewings sarcoma
Multiple Myeloma
Eosinophilic Granuloma
Malignant lymphoma of bone
Metastatic lesion
Soft-tissue tumours
(see summary)