OUTLINE Introduction Classificationof Bone tumors Clinical Presentation Staging of Bone tumors Primary Bone tumors Case Presentation
IntroductionA bone tumor is an abnormal growth of cells within a bone. The cause of bone tumors is unknown. They often occur in areas of rapid bone growth. Possible causes include:1.Genetic defects passed down throughfamilies2.Radiation3.InjuryMedline plus: Service of U.S national Library of Medicinehttp://www.nlm.nih.gov/medlineplus/ency/article/001230.htm
Introduction Cancers that start in the bones are referred to as primary bone tumors. Cancers that start in another part of the body (such as the breast, lungs, or colon) are called secondary or metastatic bone tumors.Medline plus: Service of U.S national Library of Medicinehttp://www.nlm.nih.gov/medlineplus/ency/article/001230.htm
Classification of Bone tumors Mostclassifications of bone tumors are based on the dominant tissue in the various lesions.
Clinical presentation History Examination Imaging Biopsy Important differential diagnosis
History History is often prolonged, results in delay of treatment. Patients most of the time will be completely asymptomatic until the abnormality is discovered on X-ray. This is more of benign lesions, common in children and rare after 30 Malignant tumors can be silent if they are slow growing and there is room for expansion like cavity of the pelvis.
History AGE: Useful clue. Many benign tumors present during childhood and adolescence Chondrosarcoma and fibrosarcoma typically occur in 4th and 6th decades adults. Myeloma rarely seen before 6th decade. Patients over 70 years metastatic bone lesions are more common than primary tumors.
History PAIN: common complaint and gives little indication of the nature of lesion. Progressive and unremitting pain is a very important symptom though. It may be caused by:1. Rapid expansion2. Central hemorrhage or degeneration of the tumor3. Pathological fracture.
History Swelling: Appearance of a lump, may be alarming. Neurological symptoms: Parasthesia and numbness may be caused by pressure or stretching of a peripheral nerve. Progressive dysfunction is alarming and suggests invasion by an aggressive tumor.
History Pathological fracture: may be the first and only clinical sign. In elderly people whose bones usually fracture at the cortico-cancellous junctions, if they get mid shaft fracture it is regarded as pathological until proven otherwise.
Examination If there is a lump: Where does it arise? Is it well defined or not? Soft, hard or pulsatile? Tender? Swelling can be diffuse and the overlying skin warm and inflamed which makes it hard to distinguish from infection and hematoma.
Examination Ifit is near a joint: is there any movement limitation? Spinal lesions cause muscle spasm, back stiffness or painful scoliosis. Examination will focus on symptomatic part but it should include lymph nodes, pelvis, abdomen, chest and spine.
Imaging X-ray: Most useful of all imaging techniques. There might be obvious abnormality of the bone:1. Cotrical thickening2. Discrete lump3. Cyst4. Ill-defined destruction
Imaging Is it in the metaphysis or diaphysis? Is it solitary or multiple lesions? Margins are well or ill defined? Note: cystic lesions are not necessarily hollow cavities: any radiolucent material may look like a cyst (e.g fibroma and chondroma)
Imaging If the boundaries of the cyst is well defined is mostly benign. If it is hazy and diffuse it is mostly invasive tumor. Bone surfaces: periosteal new bone formation and extension of the tumor to the soft tissues are suggestive of a malignant tumor.
Imaging Softtissues: are the muscle planes distorted by the swelling? Is there any calcification? X-rayis not a definitive diagnosis and further investigation must be done to confirm.
Imaging Other techniques of imaging used are Radinuclide scanning, CT and MRI. They all help in viewing the lesions better, view soft tissue and detect skip lesions too. Patient must not go for biopsy if MRI or CT is planned for him as it will distort the image and appearances.
Biopsy There are three ways:1.Needle biopsy: Must be performed byexperienced personal.2. Open biopsy: most reliable way ofobtaining a representative sample.3. Excisional biopsy: for benign tumors.
Staging of bone tumors Staging is the process of finding out how far the cancer may have spread. Thisis very important because the type of treatment and the outlook for recovery (prognosis) depend on the stage of the cancer.
Staging of bone tumors Intreating tumors we are facing two conflicting principles:1. Lesion must be removed widely to ensure it doesn’t recur.2. Damage must be kept minimal.
Staging of bone tumors The balance between the 2 conflicting objectives depends on knowing:1. How the tumor behaves (Aggressiveness)2. How far it has spread.The answers to these two questions areembodied in the staging system ofEnneking.
Aggressiveness Tumor Benign Malignant Latent Low Grade High Active Grade Aggressive
Enneking Staging system ofbone tumorsBenign TumorsLatent Well defined margin. Grows slowly and then stops. Remains static/heals spontaneously E.g Osteoid osteomaActive Progressive growth limited by natural barriers. Not self limiting. Tendency to recur E.g Aneurysmal Bone cystAggressive Growth not limited by natural Barriers E.g Gaint cell tumor
Enneking Staging system ofbone tumorsMalignant TumorsLow Grade Moderatly aggressive and takes a long time to metastasizeHigh Grade Very aggressive and metastasize early
Spread Assuming that there is no metastases, the local extent of the tumor is the most important factor in deciding how much tissue to be removed. Intracompartmental Spread Extracompartmental
Spread Lesions that are confined to an enclosed space (e.g Bone cavity, joint cavity or muscle group within its fascial envelope) are called Intracompartmental. Lesions that extend into interfascial or extrafascial with no natural barrier to proximal or distal spread are called Extracompartmental. (E.g pelvis, axilla)
Surgical stage Staging the tumor is an important step towards selecting the best operation suited to the patient. Bone sarcomas are divided as follows:1. Stage 1: All low grade sarcomas2. Stage 2: Histologically high grade lesions3. Stage 3: Sarcomas which have metastasized.
Surgical stages described by Enneking Stage Grade Site Metastases IA Low Intracompart No mental IB Low Extracompart No mental IIA High Intracompart No mental IIB High Extracompart No mental IIIA Low Intra/extraco Yes mpartmental IIIA High Intra/extraco Yes mpartmental
Osteoid Osteoma peak incidence in 2nd and 3rd decades, M:F = 3:1 small, round radiolucent nidus (<1 cm) surrounded by dense bone tibia and femur most common produces severe intermittent pain, mostly at night characteristically relieved by NSAIDs
Osteochondroma 2ndand 3rd decades, M:F = 1.8:1 metaphysis of long bone cartilage-capped bony spur on surface of bone may be multiple higher risk of malignant change generallyasymptomatic unless impinging on neurovascular structure malignant degeneration occurs in 1-2%
Enchondroma 2nd and 3rd decades 50% occur in the small tubular bones of the hand and foot; others in femur, humerus, ribs benign cartilagenous growth, develops in medullary cavity single/multiple enlarged rarefied areas in tubular bones lytic lesion with sharp margination and central calcification malignant degeneration occurs in 1-2%
Cystic lesions includes unicameral/solitary bone cyst (most common), fibrous cortical defect children and young adults local pain, pathological fracture or incidental detection lytic translucent area on metaphyseal side of growth plate cortex thinned/expanded; well defined lesion treatment of unicameral bone cyst with steroid injections ± bone graft
Cystic lesions Treatment treatment only necessary if symptomatic osteochondroma: resection cystic lesions: currettage and bone graft
Chondrosarcoma primary previous normal bone, patient over 40; expands into cortex to give pain, pathological fracture, flecks of calcification secondary malignant degeneration of pre-existing cartilage tumour such as enchondroma or osteochondroma most commonly occurs in pelvis, femur, ribs, scapula, humerus unresponsive to chemotherapy, treat with aggressive surgical resection + reconstruction
Ewing’s sarcoma most occur between 5-20 years old florid periosteal reaction in diaphysis of long bone moth-eaten appearance with periosteal lamellated pattern (onion-skinning) present with mild fever, anemia, leukocytosis and increased ESR metastases frequent without treatment treatment “ resection, chemotherapy, radiation survival “ 70%
Multiple myeloma most common primary malignant tumour of bone in adults 90% occur in people >40 years old present with anemia, anorexia, renal failure, nephritis, increased ESR, bone pain, compression fractures, hypercalcemia diagnosis punched-out lytic lesions on x-ray at multiple bony sites serum/urine protein electrophoresis treatment: chemotherapy, radiation, surgery for symptomatic lesions or impending fractures
References Medline plus: Service of U.S national Library of Medicine http://www.nlm.nih.gov/medlineplus/ency/article/00 1230.htm Apley’s system of orthopedics and fractures (Ninth Edition) Apley’s Concise system of orthopedics and fractures (Third Edition) American Cancer society http://www.cancer.org/Cancer/BoneCancer/Overvi ewGuide/bone-cancer-overview-staging First Aid for the USMLE Step 1 2011 Toronto notes 2009