2. OSTEOSARCOMA
•Highly malignant tumor
•Cell produces bone matrix
•Second most common primary malignant tumor of bone (20%)
•Male > Female
•Peak incident in 2nd decade
•Metaphysis of long bones
•Distal Femure > Prox Tibia > Prox Humerus
•Etiology
•Virus : polyoma virus, sv40 virus
•Radiation
•Chemicals
•Clinical Features:
•Pain : predominant symptom
•Swelling : Tender, Large (>5cm) mass. Skin over the swelling is stretched ,shiny with dilated veins. Local rise in Temp. Consistency variable
•Restriction of ROM
•Pathological #
•Edema distal to the lesion – d/t compression of venous/lymphatics
•Constitutional symptoms
•Clinical Course
•Onset – gradual, occasionally trauma precipitates symptoms
•Duration – Usually less than 6 months after onset it remains undiagnosed
•Untreated OS rapidly enlarge in size & may lead to pulmonary metastasis withing 12-18 months ( Heamatogenous route) ; Liver brain, lymphmode can be involved
•Death within 18-24 months after onset of local symptoms
•PATHO
•Gross –
•tumors violates cortex
•Associated soft tissue mass
•Variable consistency
•Yellow-brown to white
•Necrotic cysts & hemorrhage common
•Tumor may extend into medullary cavity also
•Histo-
•Hypercellular (cells are spindle shaped with cytological atypia)
•osteoid matrix may have lace like, trabecular or sheet like pattern
•multinucleated giant cells
Types :
•Primary –
•Conventional OS (Most Common) ( Subdivided in Osteoblastic, Chondroblastic & Fibroblastic)
•Low Grade intramedullary OS
•Perosteal OS
•Periosteal OS
•High Grade surface
•Telangiectic
•Small Cell OS
•Secondary –
•Post Radiation
•Paget’s Ds
•Fibrous Displasia
Classification :
1.Central (90-95%)
2.Surface
3.Extra Osseous
X ray
•Lytic, Blastic or Mixed : bone destruction and production ( More common)
•Soft tissue extension is the rule
•“Osteoblastic” Lesion – upper shaft and metaphysis are filled with dense, amorphous, neoplastic bone.
•Codman’s Triangle – triangle of subperiosteal new bone formation occurs at the upper and lower angles
•Sun-burst Appearance – spicules of neoplastic bone at right angle to the long axis of bone ,along blood vessels elevated by periosteum.
•Tc- Bone Scan
•Increased uptake by neoplastic lesion
•Use – Determine activity of lesion, Check for metastases
CT & MRI
•CT for Cortical break
•MRI for Intramedullary extend, Soft tissue invasion , Skip lesions, epiphyseal involvement
•
CXR is MUST to check for Pulmonary mets
•Angiography
Shows increased vascularity – Tumor Blush
SERUM ALKALINE PHOSPITASE:.
•A biological marker
•Elevated in only 50% cases of osteosarcoma
•Helpful in determining the prognosis
ANTISARCOMA ANTIBODIES
•Immunological marker
•These can be detected by immunohistochemical studies
•these antibodies binding to sarcoma cell surface antigens have specificity to identify the osteosarcoma.
• (not in use)
Treatment :
•Painkillers
Used on regular bases; specific analgesic for specific type of pain
•Chemotherapy
•Radiation Therapy
•Surgeries
Surgeries
1. Local Resection ( Limb Sparing Sx)
Enblock removal tumour with of all previous biopsy site and all potential contaminated tissue
2. Amputation
Commonly done procedure for osteosarcoma in past
Limb Salvage
•Removal tumor & reconstruct limb with acceptable oncological functional and cosmetic result
•And this result should be better than amputation.
•Indication : Adequate oncological “MARGIN”
•Approximately 5 cm barrier is Curative in case of Sarcoma resection
•Thick Barrier & Thin Barrier
•Contraindication for limb sparing SX
•Three strike Rule -
Bone
Nerves
Vessels
Soft Tissue envelope –skin
If ¾ involved : Not worth sparing the limb
Other Consideration for Amputation
1.Inappropriate biopsy sites
2.Infection
3.Fungating mass outside skin
4.Skeletal Immaturity ( reconstruction option not available)
5.Extensive muscle involvement
Enneking Classification for Limb Salvage
1. INTRA LESIONAL OR DEBULKING OR CURRETTAGE OF TUMOUR:
Here the dissection is within the tumour.
It leaves behind gross residual tumour tissue.
2. MARGINAL:
Here the plane of dissection passes through pseudo capsule. This marginal margin is achieved when closest plane pass through pseudo capsule.
3. WIDE EXCISION ( 3 – 5 cm MARGIN)
Here the plane of dissection passes in normal tissue so that the entire tumour remains completely surrounded by cuff of normal tissue. Frequently combined with pre or postoperative adjuvant chemo or radiotherapy
4. RADICAL EXCISION :
It is a one in which the tumour, pseudo capsule, reactive zone and entire bone as well as possibly the contagious joint apposing bone end and muscle tissue are removed as single unit