BY DR. N.O.C. ONYEMAECHI

Introduction Bone tumor is a neoplastic growth of tissue in bone. Primary neoplasms of the skeleton are rare, amounting to only 0.2 – 0.5% of the overall human tumour. Majority of neoplastic growths in bone are secondary tumors.

Classification of bone tumours Simple classification Ai. Primary ii Secondary (metastasis) - more common Primary Tumors: Bi.Benign - oma ii.Malignant - sarcoma

Primary Bone tumors are classified according to the cell of origin

Histologic TypeBenignMalignant Hematopoietic (40%) Myeloma Malignant lymphoma Chondrogenic (22%)OsteochondromaChondrosarcoma ChondromaDedifferentiated chondrosarcoma ChondroblastomaMesenchymal chondrosarcoma Chondromyxoid fibroma Osteogenic (19%)Osteoid osteomaOsteosarcoma Osteoblastoma Unknown origin (10%)Giant cell tumorEwing tumor Giant cell tumor Adamantinoma Histiocytic originFibrous histiocytomaMalignant fibrous histiocytoma FibrogenicMetaphyseal fibrous defect (fibroma)Desmoplastic fibroma Fibrosarcoma Notochordal Chordoma VascularHemangiomaHemangioendothelioma Hemangiopericytoma LipogenicLipomaLiposarcoma NeurogenicNeurilemmoma

Clinical Presentation 1. Age A useful clue. Many benign lesions present during childhood and adolescence. Ewing’s sarcoma and osteosarcoma are also common in this age group. Osteosarcoma usually has a bimodal age pattern – 2 nd decade and 6 th decade (due to Paget’s disease).

Chondrosarcoma and fibrosarcoma typically occur in older people (4 th to 6 th decade). Multiple myeloma is seldom seen before the 6 th decade. In patients over 70 years of age, metastasis is more common.

AGE(probably the most important clinical clue). Age groupMost common benign lesions Most common malignant tumors 0-20 non-ossifying fibroma fibrous dysplasia simple bone cyst aneurysmal bone cyst osteochondroma (exostosis) osteoid osteoma osteoblastoma chondroblastoma chondromyxoid fibroma eosinophilic granuloma Ewing's sarcoma metastatic neuroblastoma osteosarcoma, enchondroma giant cell tumor chondrosarcoma 40 & above osteoma metastatic tumors myeloma leukemic involvement chondrosarcoma osteosarcoma (Paget's associated) MFH chordoma

2. Pain First and most common symptom. Gives little indication of the nature of the lesion. Progressive and unremitting pain is a sinister symptom. - rapid expansion with stretching of surrounding tissues, - central haemorrhage or degeneration - malignant tumor

Osteoid osteoma – a small tumor located in the cortex gives a characteristic pain that is relieved by salicylate.

3. Swelling 2 nd most common symptom. Slowly growing – likely benign Rapidly growing – likely malignant A long standing mass is unlikely malignant. Location – which bone - what part of the bone: diaphyseal, metaphyseal, epiphyseal.

4. History of trauma So frequently associated with bone tumors. ?? Injury initiates a pathological change. Most likely draws attention to the pathology.

5. Neurological symptoms (paraesthesia, numbness) Pressure upon or stretching of a peripheral nerve. Progressive dysfunction may suggest invasion by an aggressive tumor.

6. Pathological fracture May be first and only clinical sign especially in secondary tumors. Usually follows trivial trauma.

Other Aspects of the history Any weight loss Any family history Cough Any previous treatment Any past history of masses Past medical/surgical history

Clinical Examination General examination Characterize the mass Examine the limb Systemic examination

Investigations 1.Plain X rays – the most useful imaging technique. When other imaging modalities are necessary, they must be done before under- taking a biopsy which may distort the appearances.

GENERAL PRINCIPLES OF RADIOLOGICAL DIAGNOSIS AGE WHAT BONE SOLITARY OR MULTIPLE SITE OF INVOLVEMENT LOCATION WITHIN THE BONE MARGINS SOFT TISSUE EXTENSION OSTEOLYTIC / OSTEOBLASTIC

SITE OF LONG BONE INVOLVEMENT (most primary bone tumors have favored sites within long bones; this may provide a clue to diagnosis). Diaphyseal intramedullary lesions: Ewing's sarcoma, lymphoma, myeloma. Common for fibrous dysplasia and enchondroma Metaphyseal lesions centered in the cortex: Classic location for a non-ossifying fibroma (NOF). Also, a common site for osteoid osteoma. Epiphyseal lesions: Chondroblastoma (Ch) and Giant Cell Tumor (GCT) are almost invariably centered in the epiphysis. Chondroblastoma is a rare tumor seen in children and adolescents with open growth plates. GCT is the most common tumor of epiphyses in skeletally mature individuals with closed growth plates. GCT often shows metaphyseal extension. Metaphyseal exostosis: Osteochondroma Metaphyseal intramedullary lesions: Osteosarcoma is usually centered in the metaphysis. Chondrosarcoma and fibrosarcoma often present as metaphyseal lesions. Osteoblastoma, enchondroma, fibrous dysplasia, simple bone cyst, and aneurysmal bone cyst are common in this location. Diaphyseal lesions centered in the cortex: Osteoid osteoma

2. CT Scan More accurate than plain x rays. Shows more accurately intra-osseous and extra- osseous extensions of the tumor and relationship to surrounding structures. Shows cortical erosion and presence of fractures. Can detect early pulmonary metastasis.

3. MRI Greatest value is in the assessment of tumor spread – within the bone - into nearby joint - into soft tissues

4. Radionuclide scanning (Technitium-99) Can reveal small tumors – not evident on X ray. Skeletal scintigraphy – useful in detecting skip lesions or silent secondary deposits.

5. Laboratory investigations FBC, ESR – exclude other conditions eg. Infection Serum electrophoresis – abnormal globulin fraction Bence Jones protein

6. Biopsy Open biopsy is more reliable than closed biopsy. For tumors that are almost certainly benign – an excisional biopsy may be done.

Diagnosis of Bone Tumours 1.Age of patient 2.Location of tumour 3.Radiological appearance 4.Histological features

Differential Diagnosis Soft tissue haematoma Myositis ossificans Bone infection Soft tissue sarcoma Osgood-Schlatter’s disease Gout

Staging

StageTumorLymph Node MetastasesGrade IAT1N0M0G1 or G2 IBT2N0M0G1 or G2 IIAT1N0M0G3 or G4 IIBT2N0M0G3 or G4 IIIT3N0M0Any G IVAAny TN0M1aAny G IVBAny TN1Any MAny G IVBAny TAny NM1bAny G American Joint Committee on Cancer Staging System for Primary Malignant Tumors of Bone

Note—Tx = primary tumor cannot be assessed, T0 = no evidence of primary tumor, T1 = tumor 8 cm or less in greatest dimension; T2 = tumor more than 8 cm in greatest dimension, T3 = discontinuous tumors in the primary bone; Nx = regional lymph nodes not assessed, N0 = no regional lymph node metastases, N1 = regional lymph node metastasis; Mx = distant metastasis cannot be assessed, M0 = no distant metastasis, M1 = distant metastasis, M1a = lung, M1b = other distant sites; Gx = grade cannot be assessed, G1 = well differentiated (low grade), G2 = moderately differentiated (low grade), G3 = poorly differentiated high grade), G4 = undifferentiated (high grade).

Principles of Management 1. Multidisciplinary - orthopaedic surgeon - radiologist - pathologist - oncologist - rehabilitation specialist - prosthetist

2. Benign, asymptomatic lesions – small osteochondroma Temporize Treatment may never be needed. 3. Benign symptomatic (enlarging) Marginal excision Curettage - cysts

4. Malignant tumors Treatment depends on the type of tumor and the stage. Enneking stage 11a – limb sparing operations (wide excision) + adjuvant therapy Enneking stage 11b & 111 – radical excision (amputation or disarticulation) + adjuvant therapy.

Margins of Tumor Excision 1.Intralesional excision Incomplete tumor excision Benign lesion with no risk of recurrence Debulking of incurable tumors to relieve local symptoms. 2. Marginal excion Excision through the reactive zone

Benign lesions = adequate resection Malignant lesions = 50% chance of recurrence 3. Wide excision Excision of all the tumor, reactive zone and a cuff of normal tissue. Appropriate for stage 1a For stage 11a, give chemotherapy Low rate of local recurrence – 10%

4. Radical excision Excision of the entire compartment in which the tumor lies en bloc without exposing the lesion. May involve amputation, disarticulation. For stage 11b lesions.

BENIGN TUMOURS

OSTEOCHONDROMA Also known as an exostosis, is a cartilage –capped out growth. Men are affected three times more often than women Develop in bones of endochondral origin and arise from the metaphysis near the growth plate of long bones especially about the knee

Development over time of an osteochondroma beginning with an outgrowth from the epiphyseal cartilage

Clinically present as slow growing masses Can be painful if they impinge on a nerve or if stalk is fractured. In many cases, they are detected as an incidental finding. Rarely they give rise to chondrosarcoma May be sessile or pedunculated. Osteochondroma

sessile pedunculated

DIAPHYSEAL ACLASIS Hereditary multiple exostosis. Autosomal dorminant trait – multiple osteochondromas years. 3-5% malignant transformation.

OSTEOMA Slow growing Arises from skull, paranasal sinuses and mandible Benign tumor of membranous bone consisting of dense, compact bone. In the skull, they usually arise from the outer table. Broad base with well defined margins, usually 2cm.

OSTEOID OSTEOMA Male prepondarance 2 nd to 3 rd decade Diaphysis of long bones. Round or oval area of translucency with sclerotic margin and nidus. DD-Osteoblastoma Chronic sclerosing osteomyelitis.

Osteoid osteoma of the femur

OSTEOBLASTOMA Males, second decade Similar to osteoid osteoma but >2cms Spine & flat bones Well defined radiolucency in cortex or medulla with cortical expansion. Mostly diaphyseal.

ENCHONDROMA Originates in the medullary cavity Commonly in the phalanges Sharply defined lytic lesion with endosteal scalloping Few specks of calcifications Multiple in Ollier’s disease

CHONDROBLASTOMA Years Epiphysis Most common epiphyseal tumor in children. Well defined, radiolucent,oval lesion,with thin rim of sclerosis and cortical expansion. Stippled calcification may present

GIANT CELL TUMOUR YEARS Predilection for bones adjacent to the knee and distal end of radius. Eccentrically located zone of translucency,beneath the articular cortex Soap-Bubble Appearance DD-Aneurysmal bone cyst Chondroblastoma

ANEURYSMAL BONE CYST <20yrs Predilection for long bones & DL spine X ray : Area of bone resorption with thin,expanded cortex DD-Giant cell tumours

SOLITARY BONE CYST Childhood / adolescence Always unilocular Proximal humerus and femur Metadiaphysealphyseal in location X –ray :welldefined lytic lesion, sclerotic borders, thinning of cortex DD-Chondroma Path #

NON OSSIFYING FIBROMA Eccentric in the medullary cavity yrs Around knee Xray: well marginated eccentric geographic lesion in the metadiaphysis with thin rim of sclerosis DD-Fibrous dysplasia Solitary bone cyst

INTRAOSSEOUS LIPOMA Arises in the medulla Well defined lytic lesion with sharp margins. Central ossified nodule

MALIGNANT BONE TUMOURS

OSTEOSARCOMA Most common primary malignant tumor of the bone Mesenchymal tumor Cancerous cells produce bone matrix 75 % occur in patients younger than 20 years of age

Male prepondarance years Metadiaphysis of distal end of femur and upper end of tibia

Primary osteosarcoma arise in the metaphysis of long bones of the extremities Secondary osteosarcomas occur in older patients with Paget’s disease More common in men than women Common sites are distal end of femur or proximal tibia Osteosarcoma

Osteosarcoma - conventional

Other variants Parosteal Periosteal Telangiectatic Small cell

CHONDROSARCOMA >40yrs, 2:1 Pelvis, ribs, prox femur and humerus Types: Central – intramedullary epicentre Peripheral – from surface of bone Expansile osteolytic ragged looking lesion with calcifications and soft tissue involvement

EWINGS SARCOMA Central diaphyseal lytic lesion 5-30 years Diaphysis Medullary in location Permeative destruction Lamellated / onion peel periosteal reaction Codman’s triangle Large well defined soft tissue mass. Onion peel

MULTIPLE MYELOMA Malignant B-cell lymphoproliferative disorder of the marrow. Disease of the elderly, >50yrs Well defined punched out lytic lesions all over skeleton. Increased osteoclastic activity - osteoporosis – pathological fractures. DD- Metastases

ADAMANTINOMA Eccentric location Diaphysis Well circumscribed, multiloculated Slightly expansile with cortical thinning.

METASTASES

The skeleton is one of the commonest sites of secondary cancer. In patients over 50 yrs, metastases are seen more frequently than all primary malignant tumors. The commonest source is carcinoma of breast.

Others are Prostate ca Kidney Lungs Thyroid Bladder GIT

The commonest sites for bone metastastsis are - vertebrae - Pelvis - Proximal half of the femur - Proximal half of humerus Metaststic lesions are usually multifocal Usually osteolytic. Osteoblastic lesions are uncommon – prostate ca.

OSTEOLYTIC METASTASES

OSTEOBLASTIC METASTASES

THANK YOU FOR YOUR ATTENTION!

GENERAL PRINCIPLES OF METASTASES 70% of all malignant tumours 90% Multiple 10% Solitary Types: Osteolytic – common Osteoblastic- prostate, stomach, carcinoid Mixed FEMALES 70% from Ca Breast MALES 60% from Ca Prostate Children from Neuroblastoma Exception ( CNS & BCC of skin) Below knee & elbow are rare