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Trauma & Orthopaedics Revision
PRINCIPLES OF ORTHOPAEDIC ONCOLOGY - Go to Main Contents
Classification of primary tumours of the bone:
(1) Hematopoietic
(2) Chondrogenic
(3) Osteogenic
(4) Unknown origin
(5) Fibrogenic
(6) Notochordal
(7) Vascular
(8) Lipogenic
(9) Neurogenic
(1) Hematopoietic
(2) Chondrogenic - osteochondroma, chondroma, chondroblastoma and chondromyxoid fibroma
(3) Osteogenic - osteoid osteoma and osteoblastoma
(4) Unknown origin - giant cell tumour and fibrous histiocytoma
(5) Fibrogenic - is fibroma, desmo-plastic fibroma
(6) Vascular haemangioma
(7) Lipogenic - lipoma
(8) Neurogenic neurilemmoma
(1) Hematopoietic myeloma or lymphoma
(2) Chondrogenic -
Primary chondrosarcoma
Secondary chondrosarcoma
Dedifferentiated
Mesenchymal and
Clear cell chondrosarcoma
(3) Osteogenic-
Osteosarcoma
Parosteal osteosarcoma
Periosteal osteosarcoma
(4) Tumour of unknown origin-Ewing's tumour
Malignant giant cell tumour
Adamantinoma
(5) Fibrogenic - fibrosarcoma, MFH (malignant fibrous histiocytoma)
(6) Notochordal - is chordoma
(7) Vascular- hemangioendothelioma or hemagiopericytoma
Musculo skeletal tumour society staging systems of the tumours also called Enneking System.
Main grades are:
Grade I = low grade
Grade II = high grade and
Grade III = metastatic
Each subdivided into A & B
A - Intracompartmental and
B - Extra compartmental
So we have staging system
I-A & I-B
II-A & II-B
III-A & III-B
Behaviour of the tumours:
(1) Benign latent which never become malignant
(2) Benign active
(3) Benign aggressive which are locally aggressive but do not metastasise
(4) Malignant low grade and
(5) Malignant high grade
Examples:
Benign latent - non-ossifying fibroma
Benign active - ABC
Benign aggressive - giant cell tumour
Malignant low grade - parosteal osteosarcoma
Malignant high grade - classic osteosarcoma
Preoperative evaluation for staging:
(1) Clinical examination
(2) X-ray
(3) Bone scan
(4) CT scan
(5) Magnetic resonance imaging (MRI) and
(6) Angiography
X-rays - the question need to ask:
(1) Location of the lesion
(2) Extent of the lesion
(3) What is the lesion doing to the bone?
(4) What is the bone doing to the lesion?
(5) Hint as to its tissue type
Biopsy consideration is only after staging studies are obtained. Improper biopsy site has got a very high chance of interfering with the treatment and has got major set back in limb saving procedures.
Surgical procedures can be:
(1) Intra-lesional - passes through the pseudo capsule
(2) Marginal - entire lesion is removed but the pseudo capsule is left
(3) Wide or intra compartmental is en-block resection and
(4) Radical which is extra compartmental
Malignant bone tumours are of 3 types
(1) Mesenchymal cells (sarcomas)
(2) Bone marrow cells (myeloma and lymphoma) and
(3) Metastasis
Osteosarcoma and Ewing's sarcoma are the most common mesenchymal bone tumours occurring during childhood and adolescence. Above the age of 40, metastatic bone tumours are the most common tumours. Multiple myeloma and metastatic carcinoma typically increase in frequency with increasing patient age.
Osteosarcoma is a high grade malignant spindle cell tumour arising within a bone and the characteristic feature is production of tumour osteoid.
Macroscopic classification of osteosarcoma:
(1) Central (typical) osteosarcoma - which is subclassified on the microscopic ground as osteoblastic chondroblastic telangiectatic low grade osteosarcomas
(2) Surface osteosarcomas - subclassified: parosteal (low grade) periosteal and high grade surface OS
(3) Osteosarcoma of the jaw
(4) Multicentric osteosarcoma
(5) Secondary osteosarcomas due to -Paget's -Post radiation or -Dedifferentiated chondrosarcoma
(6) Osteosarcoma derived from benign precursors
Microscopy: Spindle cell sarcoma producing osteoid
Most common sites for osteosarcomas are around the knee joint - 50% and proximal humerus - 25%
Radiographic characteristics are described by Wilner as:
32% - Sclerotic
22% - Osteolytic and
46% - Mixed osteosarcomas
Chemotherapeutic protocol has been combination of drugs (mnemonic: MAC): High dose Methotrexate, Adriamycin and Cisplatin.
Limb sparing resection in malignant tumours - three phases -
(1) Resection of tumour
(2) Skeletal reconstruction
(3) Soft tissue and muscle transfers
Contraindication to limb sparing surgery:
(1) Major neurovascular involvement
(2) Pathological fractures
(3) Inappropriate biopsy site
(4) Infection
(5) Immature skeletal age
(6) Extensive muscle involvement
Easy way to remember is - Six 'I's
(1) Involvement of the vessels and nerves
(2) Involvement of muscles extensively
(3) Injury
(4) Inappropriate biopsy site
(5) Infection
(6) Immature skeletal age
Parosteal osteosarcoma is low grade tumour, typically involves the femoral condyles.
Periosteal osteosarcoma is high grade lesion in contrast to parosteal osteosarcoma.
Chondrosarcoma is a cartilaginous tumour without evidence of direct osteoid formation. 5 types are described:
(1) Central
(2) Peripheral
(3) Mesenchymal
(4) Dedifferentiated and
(5) Clear cells
Half of all chondrosarcomas arise above the age of 40 years. Most common sites are pelvis, femur, and shoulder girdle.
Chondrosarcomas are low grade tumours except mesenchymal and dedifferentiated chondrosarcomas, which are rare but high grade tumours.
Microscopy: Single or multi-nucleated giant cartilage cells.
Radiographic findings can be
(1) Lytic lesion with faint calcification - is most common
(2) Diffuse without any sclerotic border - highly malignant
(3) Key sign of malignancy is endosteal scalloping
Treatment of chondrosarcoma is surgical removal.
Locally aggressive tumour. 75% of them occur around the knee joint. 2 to 8% chances that these may undergo malignant transformation. Commonly appears after skeletal maturity and the counterpart of that tumour is osteoclastoma, which appears before epiphyseal closure. Microscopically giant cells are seen in abundance.
Treatment: Surgical removal en-block - 90% curative; curettage with or without bone graft has 40 to 75% recurrence rate.
Marcove popularised curettage and cryosurgery using liquid nitrogen -20 to - 400 centigrade.
Other methods: radiation therapy and PMMA reconstruction of the defect.
Histological pattern is herringbone pattern of interlacing bundles of collagen fibres. Fibrosarcoma occurs in middle age, either central or cortical.
Malignant Fibrous Histiocytosis, microscopy shows cogwheel pattern of collagen fibres, spindle cells.
Ewing's Sarcoma: Second most common bone sarcoma of childhood. Characteristically affects flat and axial bones - 50 to 60%. Long bones mainly diaphyseal segment is involved.
Microscopy: Poorly differentiated small round cells with marked homogeneity
Radiographically Ewing's tumour is commonly a highly destructive radiolucent osteolytic lesion. Sun burst or onion peel appearance seen in Ewings is because of periosteal elevation and periosteal reaction.
Musculoskeletal staging system does not apply to round cell sarcomas of the bone because of the predilection for the lymphatic cells of Ewing's sarcoma and round cell sarcomas.
Treatment: Ewing's are generally radiosensitive. Surgical resection is becoming increasingly popular. Multidrug chemotherapy is also used. Radiation dose 4500 to 6000 CGy. 1000 to 1500 CGy to the tumour site.
Most commonly affects spine and ribs. Age between 50 - 80 years. Radiological appearance of punched out lesion. Renal failure is a common complication.
Criteria for solitary plasmacytoma:
1. Solitary lesion
2. Histological diagnosis
3. Marrow plasmacytosis < 10%
Microscopy: Plasma cells are seen. Well differentiated plasma cells will have eccentric nucleus, peripheral chromatin - clock face appearance.
Treatment:
(1) Multiagent chemotherapy
(2) Solitary : Radiotherapy
(3) Treatment of complications
Most common bone tumour in patients over 40. Bone scan is highly accurate. Most common sites involved are spine, pelvis, femur and ribs.
Radiographic findings: osteolytic are the most common. Osteoblastic metastasis can occur in breast, prostate, lung and bladder tumours.
Treatment in metastatic bone diseases:
Goals of treatment -
(1) Pain relief
(2) Prevention of fractures
(3) Continued ambulation
(4) Avoid cord compression and the treatment is highly individualised
Osteoid osteomas are less than 10 mms in diameter and if the bone forming tumour is more than 15 mms in diameter its called Osteoblastomas.
Chondroblastomas typically arise in the epiphyses of a skeletally immature child.
Benign lesion most commonly affecting proximal humerus and involves metaphyses and/or diaphyses of the long bone. Radiolucent and slightly expansile with well defined margins. Cold on bone scan. Lesion is central in nature as against eccentric lesion of fibrous dysplasia or aneurysmal bone cyst. Aspiration will yield yellow fluid in UBC and blood in ABC.
Treatment options:
(1) Aspiration
(2) Flushing and injection with methyl prednisolone acetate and
(3) Intra lesion injections of autogenous marrow.
