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Paul Banaszkiewicz Paul Banaszkiewicz Section Editor
Rebecca Rebecca Mazel Segment Author
Nicole Nicole Abdul Segment Author

Principles and diagnosis

  • Nomenclature:
  • Primary bone tumours are one of three types:
    • Benign
    1. Malignant
    2. Lesions that simulate bone tumours (tumour mimics)
  • This is not a classification however. Historically, tumours are classified (as opposed to staged) according to the predominant tissue type expressed within the lesion.

Histology type

Benign

Malignant

 Haematopoietic

 

Myeloma

 

 

Lymphoma

 Chondrogenic

 Osteochondroma

Chondrosarcoma

 

 Chondroma

 

 

 Chondroblastoma

 

 

 Chondromyxoid fibroma

 

 Osteogenic

 Osteoid Osteoma

 Osteosarcoma

 

 Osteoblastoma

 

 Fibrogenic

 Fibroma

 Fibrosarcoma

 Lipogenic

 Lipoma

 Liposarcoma

 Neurogenic

 Neurilemoma/Schwannoma

 

 Notochordal vascular

 Haemangioma

 Haemangioendothelioma

 Unknown origin

 Giant cell tumour

 High grade (pleomorphic) sarcoma

 

 Histiocytoma

 Ewing’s tumour

 

 

 Malignant GCT

 

 

 Adamantinoma

  • Although a useful tool, there are drawbacks:
    • The most predominant tissue type is not necessarily the tissue of origin.
    • No pathological or clinical correlation between the conditions in any one category.
    • Often no relationship between the benign and malignant conditions with similar tissue types.
    • Some tumours named as a single entity (e.g. osteosarcoma have several subtypes with very different behaviour).
  • Staging:

Why?

  1. To understand how far the tumour has spread.

  2. To assess how aggressively it will behave in its current location.

  • It is only through assessing these parameters that the resection type can be planned to balance the needs of an adequate resection against curative surgery.

How

  • Staging systems are based on:
    • Histological grade (G)
    • Site (T)
    • Metastases (M)
  • Enneking staging system was tested retrospectively on 397 cases of bone and soft tissue tumours.
  • Shown that prognosis varied with the stage.

NB. Applies to lesions of connective tissue, not primary lesions of round cell origin (e.g. leukaemia’s, lymphomas, myeloma or Ewing’s).

Enneking's surgical stages

 Stage

Grade

Site

Metastases

  1A

  1B

Low (G1)

Low (G1)

Intracompartmental (T1)

Extracompartmental (T2)

No (M0)

No (M0)

  2A

  2B

High (G2)

High (G2)

Intracompartmental (T1)

Extracompartmental (T2)

No (M0)

No (M0)

  3

Low (G1) or high (G2)

Intracompartmental (T1) or extracompartmental (T2)

Yes (M1)

Tumour grade

  • This is the assessment of the aggressiveness of the tumour:
    • G0 Histologically benign (well differentiated and low cell to matrix ratio).
    • G1 Low grade malignant (few mitoses, moderate differentiation and local spread only). Have low risk of metastases.
    • G2 High grade malignancy (frequent mitoses, poorly differentiated). High risk of metastases.
  • Aggressive or high grade tumours have several histological features:
    • Cellular atypia
    • Frequent mitoses (Indicates highly active)
    • Extensive necrosis
    • Significantly vascular
    • Small amounts of immature matrix

Tumour site

  • T0 Intracapsular
  • T1 Intracompartmental (e.g. cortical bone, joint capsule or fascia)
  • T2 Extracompartmental (spreads beyond “fascial” plane without longitudinal containment). Bone and periosteum are separate compartments.

Intracompartmental

Extracompartmental

Intraosseous

Soft tissue extension

Intra-articular

Deep fascial extension

Intrafascial compartments:

Ray of hand or foot

Posterior or anterior leg

Ant, med, post thigh

Buttocks

Volar or dorsal forearm

Anterior or posterior arm

Pericapsular

Extrafascial planes/spaces: (neurovascular containing spaces)

Mid & hind foot/mid hand

Popliteal fossa

Groin – femoral triangle

Intra-pelvic

Antecubital fossa

Axilla

Paraspinal

Tumour work-up

  • The goals of the tumour work-up are to identify the type and extent (staging) of the tumour, specifically its tissue of origin remembering that the most common bone tumours are metastases.

1. History and clinical examination (age, sex, site and past history especially malignancy).

  • Thyroid
  • Breasts
  • Chest
  • Liver
  • Kidney
  • Rectal (prostate and rectal tumours)

2. Bloods:

  • FBC

Underlying Hb

Leukaemic cells, etc.

  • ESR (often elevated)
  • Biochemistry
    • Baseline liver and renal function before potent cytotoxic therapy

    • Screen for metastases: Ca2+, PO4, liver enzymes and alkaline phosphatase

  • Acid phosphatase (prostate and increased with metastatic deposits)
  • Thyroid function tests
  • PSA
  • Serum protein electrophoresis (myeloma)

3. Urinalysis
4. Urine Bence–Jones (myeloma)
5. CXR
6. Abdominal ultrasound
7. Bone scan (PET–CT scan) ® other sites
8. MRI ® soft tissue extent and association with nerves and vessels
9. CT of lesion and chest (® staging)
10. Angiography ® tumour blood supply and relationship to major vessels
11. Biopsy

Bone tumour diagnosis

  • Before the biopsy is taken it is often possible to either identify or at least reduce the differential diagnosis of a bone tumour through assessing:
  • Radiographic features
  • Patient’s age and history
  • Location of the tumour

Plain radiography

  • These will almost always be the first examination to be performed. The plain X-ray can reveal characteristic features diagnostic of particular tumour types. Evaluation depends on assessing the effect of the lesion on the bone and the response of the bone to the lesion.
    • Multiple lesions will be more likely to be metastases.
    • Slow growing lesions will allow the bone to react to the formation of the lesion and a narrow zone of transition will occur.
    • Rapidly growing lesions will have a permeative appearance with a wide zone of transition.
    • Codman's triangle: forms when a subperiosteal lesion elevates the periosteum only allowing bone formation at the margin.
    • Sunray spiculation: caused by attempts at bone formation by the periosteum overlying the lesion.
    • Cartilage tumours will also have speckled calcification within the tumour.
    • Endosteal scalloping: cortical resorption caused by aggressive medullary lesions. Less aggressive lesions cause bony expansion.

Note: For a lesion to appear as lytic on plain X-ray at least 50% of the bone must have been destroyed.

BSBONETUMOURPRINCIPLES 3.png     BSBONETUMOURPRINCIPLES 4.png

Codman’s Triangle in Periosteal Osteosarcoma                                                        Sunray Spiculation in Osteosarcoma

 Case courtesy of Dr Subash Thapa, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/40937">rID: 40937</a>

Mnemonic for lucent bone lesions = FOGMACHINES

  • F ibrous dysplasia
  • O steoblastoma
  • G iant cell tumour
  • M etastasis/myeloma
  • A neurysmal bone cyst
  • C hondroblastoma/chondromyxoid fibroma
  • H yperparathyroidism (brown tumour)/haemangioma
  • I nfection
  • N on-ossifying fibroma
  • E osinophilic granuloma/enchondroma
  • S imple bone cyst

Mnemonic for sclerotic bone lesions = VINDICATE

  • V ascular: haemangiomas, infarct
  • I nfection: chronic osteomyelitis
  • N eoplasm
  • D rugs: vitamin D, fluoride
  • I nflammatory/idiopathic
  • C ongenital: bone islands, osteopoikilosis, osteopetrosis
  • A utoimmune
  • T rauma: stress #
  • E ndocrine/metabolic: hyperparathyroidism, Paget’s disease

Bone scan

  • Useful in the screen for occult metastases.
  • Bisphosphonates labelled with technetium 99 usually used in dose of 500–600 mBq.
  • Osteoid osteoma ® increased activity in blood pool phase as well as delayed bony phase.
  • Inflammatory lesions also increased activity in blood pool scan.
  • Gallium 67 has also been utilised.

Superceded in many centres by PET–CT scan.

PET–CT scan (positron emission tomography – computed tomography)

  • Diagnosis of occult metastases/staging.
  • Assessment of response to treatment.
  • Labelled radiopharmaceutical (typically 2-fluoro-2-deoxy-d-glucose (FDG)) is injected intravenously.
  • FDG metabolised by tumour cells and therefore accumulates in them. This is measured.
  • Fused PET and CT images obtained.

CT scans

  • Indicates extent of bony involvement/destruction.
  • Good for detecting subtle cortical disruption, fracture, calcification or ossification.
  • Not as good as MRI for soft tissue extent. Can detect soft tissue masses ³5 mm diam.
  • Useful to stage – e.g. lung/visceral secondaries.

Angiography

  • Feeding vessels identified as well as the tumour proximity to major vessels.
  • Displacement of vessels by tumour ® access for excision of the tumour.
  • Embolisation of vascular tumour prior to surgery (renal metastases typically).
  • Intra-arterial chemotherapy.
  • Rarely used apart from embolisation (superceded by CT or magnetic resonance angiography).

MRI

  • Good soft tissue definition (better than CT) and extra-osseous extension, joint involvement, skip lesions and epiphysial extension ® staging ® extent of tumour both intra and extramedullary.
  • Able to image in any plane – thus good for pelvic/sacral lesions.
  • T1 weighted images best for looking at extent of marrow involvement and T2 more useful for evaluating cortical bone and soft tissue extent (NB. CT better for showing areas of calcification/ossification).
  • Best technique to identify haemorrhage/oedema/inflammation – e.g. prior biopsy:
    • Oedema usually surrounds malignant lesions and is unusual around benign tumours.
    • Most tumours are dark on T1 and bright on T2.
    • Desmoids, scar tissue, fibrous tissue and cortical bone are dark on T1 and T2.
    • Lipomas, liposarcomas and haemangiomas are bright on T1 and T2.

 

Benign

Malignant

Other

 Birth– 5 years

Eosinophilic granuloma [onion skin periosteal Rxn]

(Unicameral bone cyst – rare)

Leukaemia

Metastatic neuroblastoma

Osteomyelitis

healing/stress fracture

 6–18 years

Unicameral bone cyst

Aneurysmal bone cyst

Non-ossifying fibroma

Eosinophilic granuloma

Enchondroma

Chondroblastoma

Chondromyxoidfibroma

Osteoblastoma

Ewing’s sarcoma

Osteosarcoma

Osteomyelitis

Fibrous dysplasia

Osteofibrous dysplasia

 19–40 years

Giant cell tumour

Eosinophilic granuloma

Ewing’s sarcoma

 

 40+ years

 

Metastases (lung, breast, prostate, renal, thyroid, colon)

Multiple myeloma

Lymphoma

Osteosarcoma (Paget’s)

Chondrosarcoma

Pleomorphic sarcoma

Hyperparathyroidism

Osteomyelitis

Paget’s

 

  • Phemister’s law = the most common site of infection & tumours is the fastest growing site of the long bone.

BSBONETUMOURPRINCIPLES 1.jpg

Figure 1. Tumour location made simple

  • Juxta-cortical lesions:
    • Parosteal osteosarcoma – no space between lesion and cortex.
    • Myositis ossificans – space between lesion and cortex.
    • Osteocartilagenous exostoses (cartilage capped) – shares cortex with bone (medullary continuity).
BSBONETUMOURPRINCIPLES 6.pngBSBONETUMOURPRINCIPLES 7.png
Myositis ossificans                                                                                   Parosteal osteosarcoma
BSBONETUMOURPRINCIPLES 5.png
Osteocartilagenous exostosis (enchondroma)
 
Certain bones in the body can be considered “epiphyseal equivalents” for purposes of differential diagnosis. These include the patella, the calcaneus, and most apophyses. Therefore, for lucent lesions in these areas, one should include the classic epiphyseal entities such as chondroblastoma (children), giant cell tumours (adults) and aneurysmal bone cysts.

Gracile bones

Osteogenesis imperfecta

Erlenmeyer flask

Gaucher’s disease

Scallops from without

Neurofibromatosis

Scallops from within

Fibrous dysplasia

Ground glass

Fibrous dysplasia

Salt and pepper skull

Paget’s disease

Stress lines

Paget’s disease (on convex/tension side of bone)

Looser’s lines

Rickets/osteomalacia (on concave/compression side of bone)

Smoke goes up a chimney

Medullary infarct

Punched-out lesion

Eosinophilic granuloma

Rat-bite lesions

Congenital syphilis

Soap bubble

Giant cell tumour

Pencil in cup

Aneurysmal bone cyst

Blow-out

Aneurysmal bone cyst

Nidus

Osteoid osteoma

Popcorn calcification

Cartilage tumours

Sled runner tracks

Ollier’s and Mafucci’s

Sunray spiculation

Osteosarcoma

Permeative pattern

Round cell tumours

Moth-eaten

Round cell tumours

  • Principles:
  1. Should know probable diagnosis and stage of tumour before biopsy as it is the last step in the staging of the patient.
  2. Performed by or in conjunction with the surgeon who will perform the definitive surgery (? biopsy ® frozen section ® definitive surgery during the same anaesthetic for presumed metastases).
  3. Biopsy tract orientation and location is critical – will need to be resected in the definitive surgery if lesion is malignant.
  4. Meticulous haemostasis to avoid tracking haematomas.
  5. Send samples for microbiological analysis.
Open biopsy
  • Aim for excisional biopsy when possible for benign lesions.
  • Needle biopsy or Incisional biopsy preferable in potentially malignant lesions.
  • After consultation with the pathologist, radiologist and definitively managing surgeon.
  1. Longitudinal incision.
  2. Sharp dissection should proceed directly to the tumour, through muscle not between muscle planes.
  3. Uninvolved anatomic compartments should not be exposed.
  4. Avoid all major neurovascular structures to prevent contamination.
  5. Excise block of reactive tissue, pseudo capsule, capsule, and block of tumour ® formalin with or without frozen section.
  6. Windows in bone should be as small as possible and oval to avoid stress risers and pathological fracture.
  7. Release tourniquet prior to closure ® haemostasis.
  8. Close with a subcuticular stitch.
  9. Drains should come out through the wound.
  10. If proceed following biopsy ® new instruments and drapes to stop seeding.

Needle biopsy (preferred for potentially malignant lesions)

  1. As for open biopsy.
  2. Place the biopsy tract where it can be excised.
  3. Fine needle biopsy (popular in Scandinavia):
  • Relies on cytological interpretation by an experienced pathologist.
  • Accuracy = 65–95% (determined by the adequacy of the collected tissue sample).
  • Does not allow for immunohistochemical analysis.

4. Core needle biopsy:

  • Uses trocar cannula system (e.g. Jamshidi), with an outer sleeve which closes over the trocar, capturing the sample of tissue.
  • Provides more tissue than fine needle and allows for immunohistochemical analysis.
  • Accuracy = 75–95%.

5. Disadvantage of needle biopsy = tissue obtained may be from necrotic portion of tumour and therefore not suitable for diagnosis, or tissue may be reactive in nature and not representative of actual tumour. Frozen section may thus be beneficial.

Frozen section

  1. Able to determine if specimen is adequate or representative.
  2. Can decide if lesion is inflammatory and needs culturing.
  3. Can determine if there is need to perform further investigations/tests.
  4. Immediate diagnosis possible – can proceed to definitive surgery.

The goal of treatment is to remove the lesion with minimal risk of local recurrence. A basic tenet is that attempted limb salvage surgery should not compromise the prognosis of the patient (recurrence rate no worse than amputation) and the residual limb should be functional.

Limb salvage

  • Criteria for limb salvage:

          -Local control of the lesion must be at least equal to amputation.
          -The saved limb must be functional.

  • Types of osseous resection:

          -Intercalary (between joints).
          -Intra-articular (one side of joint).
          -Extra-articular (both sides of the joint).

  • Various methods of salvage, e.g, endoprosthesis, allograft, composite, arthrodesis (allograft).
  • Relative contraindications:

         -Pathological fractures.
         -Skeletal immaturity.
         -Must be in an anatomical location which favours reconstruction and allows wide surgical margins.
         -The presence of distal metastasis is not a contraindication.

Surgical margins (Musculoskeletal Tumour Society)

1. Intra-lesional:

  • Through the tumour.
  • Leaves macroscopic tumour.
  • Not therapeutic.

2. Marginal:

  • Through pseudo-capsule of tumour/reactive zone (contains inflammatory cells, oedema, fibrous tissue, satellites of tumour cells).
  • Controls non-invasive benign tumours.
  • Recurrence of malignant tumours = 25–50%.

3. Wide:

  • Around reactive zone, leaving a cuff of normal tissue.
  • Skip lesions left.
  • Recurrence of malignant tumours = <10%.

4. Radical:

  • Removal of entire compartment or compartments.
  • Distant metastases left.

5. Amputation:

  • Should be thought of as a form of reconstruction in which surgical control of the tumour precludes useful function.
  • Indications for amputation now include:
    • Tumour resection is impossible due to neurovascular invasion.
    • Tumour excision requires excessive muscle excision.
    • Significant contamination following a pathological fracture.
  • Can be administered as neo-adjuvant (induction) and adjuvant (postoperative).

Neo-adjuvant chemotherapy

  • = Staging ® Chemotherapy ® Restaging ® Surgery ® Tumour kill rate ® Further treatment (change chemo or introduce radiotherapy as indicated).
  • Enables action of agents against tumour to commence immediately.
  • Efficacy of chemotherapeutic agents evident at the time of tumour resection.
  • Reduces the mass and vascularity of the tumour prior to definitive surgery.
  • Enables time for operative planning (manufacture of custom implants).
  • Ideally >90% kill rate and if <90% then change agents.
  • No increased survival evident with different agents in those who do not respond to the initial treatment (? just identifies those patients with a good prognosis).
  • Commence adjuvant treatment once the wound has healed.
  • May persist for 2 months to 2 years depending on the response.
  • Localised disease = 60–70% long-term disease-free survival.
  • May lead to:

        -Stunting of growth (may catch up later).
        -Osteoporosis.
        -AVN.
        -Cisplatinum ® nephrotoxicity and hearing loss.
        -Adriamycin ® cardiotoxicity.
        -Vincristine ® neurotoxicity.
        -Chemotherapeutic induced malignancy usually blood forming, e.g. leukaemias but also may ® cancer of bladder or skin (particularly associated with cyclophosphamide).

Methotrexate

  • Binds to dihydrofolate reductase and therefore blocks purine synthesis.
  • Citravorum factor “rescue” replenishes the folate pool.
  • Potentiates the effects of radiotherapy.

Adriamycin

  • Cytotoxic antibiotic.
  • Also potentiates radiotherapy.
  • Preoperative radiotherapy may reduce size of the tumour, decrease chance of seeding at the time of resection or if seeding then decrease chance of viability of the shed cells.

Effect of radiation

  • Direct = absorption by complex molecules causes rupture of chemical bonds with damaging effects.
  • Indirect = by ionisation and formation of highly reactive intracellular free radicals ® DNA changes ® stop cell reproduction and slow cell turnover ® loss of specific cell function.
  • The effect on cancer cells not due to more rapid growth of cells but the capacity for recovery and repair of normal tissues compared with the poor capacity of cancer tissues.
  • Destruction of small blood vessels on which growth of a tumour depends also contributes to the effect and induction of an inflammatory response may ® destruction of cells weakened by radiation.
  • Increased sensitivity of cells in the presence of oxygen up to a critical level but above this level (about that of normal atmospheric pressure) sensitivity does not increase appreciably (hypoxic tissue has decreased radio sensitivity).
  • Radiosensitivity of a tissue is directly proportional to its mitotic activity and inversely proportional to the degree of differentiation of its cells.

Adverse effects

  • Joint ® stiffness and loss of function (treatment = physiotherapy).
  • Subcutaneous fibrosis.
  • Children ® premature fusion of growth plates.
  • Radiation-induced sarcoma.
  • Enteritis, diarrhoea, obstruction and bleeding.
  • Cystitis and hepatitis.
  • Scoliosis may develop therefore include both sides of vertebrae.
  • Muscle atrophy and fibrosis.
  • Erythema of skin and hyperpigmentation.
  • Hair loss and skin flaking.
  • Lymphoedema ® need to screen a strip of skin ® lymphatic drainage.

Definitions

  • Rad (radiation absorbed dose) is a measure of the energy imparted to the matter by ionising radiation per unit mass (1 rad = 100 erg/g (0.01j/kg).
  • Grays (Gr) = 1 joule of energy absorbed by a mass of 1 kg (equivalent to 100 rad).

CASE BASED DISCUSSIONS

Case based Discusson Tumour Principles

You are on call in a DGH when you are referred a 19-year old traveller who is in ambulatory care with 3 months of a painful swollen lower leg. USS is negative for DVT, but shows a large poorly  defined mass. They have performed X-rays which show the following:

Examiner:Describe these x-rays

BSBONETUMOURPRINCIPLESCBD1.pngBSBONETUMOURPRINCIPLESCBD2.png

Images courtesy of Dr Aditya Shetty, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/27260">rID: 27260</a>

Candidate:Poorly defined calcified lesion affecting the left distal third of the tibia and fibula. Wide zone of transition. Sunray spiculation suggestive of extensive soft tissue involvement

Examiner:Is it benign or malignant?

Candidate:This is highly suspicious of a malignant bone tumour

Examiner:What is your understanding of Enneking staging?

Candidate:Enneking staging is commonly used to describe bone tumours, based on histology, site, and metastases. Grade is low (G1) or high (G2). Site is intracompartmental (T1) or extracompartmental (T2). Metastases are not present (M0), or are present (M1).

Examiner:How are you going to maange this patient

Candidate:I would normally refer him onto our local musculoskeletal tumour unit for further management

My understanding of the principles of management of this lesion would be to first stage the tumour
I would want to get more information, so I would take a full history and examination. I would also want to get more imaging of the lesion with an MRI and CT scan
I would attempt to stage the tumour with a CT scan of the chest,abdomen and pelvis

Previous
Next

QUESTION 1 OF 3

You see a 21 year old male in clinic with knee pain. Radiographs show a sclerotic lesion with a wide zone of transition(ill defined) along with cortical destruction(Codman,Sunray) and expansion into soft tissues.You are highly suspicious of an osteosarcoma. Which of the following is the most appropriate next step

QUESTION ID: 33

1. Order an urgent local MRI, and CT chest abdomen and pelvis
2. Order an urgent local MRI, CT chest abdomen and pelvis. Book onto the next available theatre list for a biopsy and refer to the closest sarcoma MDT once the histology results are back.
3. Refer the patient on to the bone tumour MDT
4. Stage the tumour, perform screening bloods, and book onto the next available theatre list for a biopsy
5. Take a comprehensive history and perform a full examination the patient.

QUESTION 2 OF 3

You have asked advice from your local bone MDT about a lesion in the proximal femur which is thought to be a metastatic secondary deposit from the breast. The MDT are happy for you to perform a biopsy as you had worked in the department as part of your orthopaedic training and performed previous biopsies. The principles of biopsy would include

QUESTION ID: 34

1. Any cut made by the biopsy should be on a tract that can later be removed
2. Bleeding tissue helps evacuate the tumour, and should be encouraged
3. Most tissue should be taken from the centre of the lesion
4. The biopsy should be done as soon as possible, even if this means not having detailed imaging beforehand
5. Transverse incisions are better because they open more tissue planes and increase the chance of getting a positive sample

QUESTION 3 OF 3

A 12 year old female patient has had a biopsy of a suspicious lesion in the distal femur performed by the regional sarcoma MDT unit.The lesion is confirmed as an osteosarcoma. They are listed for an excision of the tumour. This should be:

QUESTION ID: 35

1. A. Intra-lesional, removing the soft tissue component only so that the patient can mobilise immediately afterward. Residual tumour can be removed later.
2. A. Limb preserving, provided the risk of recurrence is not compromised
3. A. Margins should be determined by frozen section in theatre
4. Above knee amputation, to ensure the entire tumour is removed
5. Rotationplasty so long as the main nerves in the lower leg ca be salvaged

References

  • 1. Enneking WF, Spanier SS, Goodman MA. A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop 1980 Nov-Dec; 153: 106–120. A surgical staging system for musculoskeletal sarcomas stratifies bone and soft-tissue lesions of any histogenesis by the grade of biologic aggressiveness, by the anatomic setting, and by the presence of metastasis. The three stages: I – low grade; II – high grade; and III – presence of metastases, are subdivided by (a) whether the lesion is anatomically confined within well-delineated surgical compartments, or (b) beyond such compartments in ill-defined fascial planes and spaces. Operative margins are defined as intralesional, marginal, wide, and radical, and relate the surgical margin to the lesion, its reactive zone, and anatomic compartment. The system defines prognostically significant progressive stages of risk which also have surgical implications. When the system is linked to clearly defined surgical procedures, it permits appropriate evaluation and comparison of the new treatment protocols designed to replace standard surgical treatment.
  • 2. Enneking WF, Spanier SS, Goodman MA. Current concepts review. The surgical staging of musculoskeletal sarcoma. J Bone Joint Surg Am 1980 Sept; 62(6): 1027–1030.