Osteosarcoma

04/08/23 1

OsteosarcomaPaul Duffy

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OverviewDefinition

Epidemiology

Pathogenesis

Skeletal distribution

Clinical presentation

Evaluation

High grade osteosarcoma

Parosteal osteosarcomaPeriosteal osteosarcomaHigh grade surface osteosarcoma

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Definition

2nd most common primary bone tumor

Malignant tumor of mesenchymal origin

Spindle shaped cells that produce osteoid

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Epidemiology

Any age

75% 12-25yrs

Modal incidence

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Epidemiology

Primary vs secondary

Male : female

Li Fraunie syndrome

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PathogenesisUnknown

Modal incidence correlates with rapid bone growth

Radiation exposure

Cancer survivors

Retinoblastoma

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Skeletal distribution

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Classification

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Clinical Presentation

Painful mass arising from bone

Trauma

Metastisize early in evolution20% clinically detectable mets at dx

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Evaluation

Suspected diagnosis by hx and physical

Supported by xray

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Plain Xray

Lytic, sclerotic or mixed

Typical characteristics of malignant tumor

Enneking’s 4 questions

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Initial Evaluation

Define the extent of the disease

Locally

Systemically

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Local

CT

MRI

+/- Angiogram

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CT

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MRI

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Angio

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Systemic

Bone scan

CT Chest

lab

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Classic High Grade Osteosarc

Age, sex

Presentation

Physical exam

Blood work

Plain filmsSite

size

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Differential Dx

Giant Cell Tumor

Aneursymal Bone Cyst

Ewings

Osteoblastoma

Metastasis

Lymphoma

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Biopsy

Principles

Dx “high grade osteosarcoma”

Now What??

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Chemotherapy

Micro metastasis

What we have learned pre chemo (1970’s)

Multi Institutional Osteosarcoma Study

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Chemotherapy

Chemo cannot control clinically detectable disease

Radiation is ineffective

Local control is surgical

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ChemotherapyBest protocol is subject of ongoing trials

DrugsDoxorubicinCisplatinIfosfamideMethotrexateCyclophosphamide

Side effects

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Induction Chemotherapy

Arose in conjunction with development of limb sparing surgery

Increase survival

prognostic

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Surgery

Limb salvage the norm

Now safer procedure

Wide surgical margin

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Surgical options

Articular surface removedOsteoarticular allograft replacementCustom modular prosthesisAllograft prosthesis compositeAllograft arthodesis

Segment of diaphysis missingIntercalary allograft

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Surgery

Young patient with open growth plateRotatioplasty

Conventional amputation

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Surgery

Indication for amputationGrossly displaced pathologic fracture

Encasement of neurovascular bundle

Tumor that enlarges during preop chemo and is adjacent to neurovascular bundle

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Current Standard of Care

Pretreatment radiologic staging

Bx to confirm diagnosis

Preoperative chemotherapy

Repeat radiologic staging(access chemo response, finalize surgical tx plan)

Surgical resection with wide margin

Reconstruction using one of many technoques

Post op chemo based on preop response

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Surface osteosarcoma

Parosteal

Periosteal

High grade surface osteosarcoma

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Parosteal

5% of osteosarcomas

Posterior metaphysis of distal femur

Slow growing large ossified mass

Confused with osteochondroma

String sign

Low grade

treatment

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Parosteal Osteosarcoma

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Parosteal Osteosarcoma

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Periosteal Osteosarcoma

Arises from surface of diaphysis

Characterized by bony spicule formation perpendicular to shaft

Sunburst

Low grade

Wide excision

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High grade surface

Very rare

20-30’s

Appearance as parosteal but histology high grade

Tx as classic intermedullary