Bone tumour , enchondroma , osteochondroma

neoplasia

1. CLASSIFICATION OF BONE TUMOURS AND GENERAL PRINCIPLES OF MANAGEMENT

2. Introduction : Neoplasia : It is defined as a mass of tissue formed as result of abnormal, excessive, uncoordinated, autonomous and purposeless proliferation of cells. Term Neoplasia includes both Benign and Malignant.

3. FEATURES BENIGN (DIFFERENTIATED) MALIGNANT (UNDIFFERENTIATED) MACROSCOPIC FEATURES Boundaries Encapsulated or well circumscribed Poorly circumscribed and irregular Surrounding tissue Often compressed Usually invaded Secondary Changes Occur less often Occur more often MICROSCOPIC FEATURES Pattern Usually resemble tissue of origin No resemblance Nucleo – Cytoplasmic Ratio Normal Increased Pleomorphism Absent usually Often present Anisonucleosis Absent Generally present Hyperchromatism Absent Often present Growth Rate Usually Slow Rapid Metastasis Absent Frequently Present Contrasting Differences between Benign and Malignant Tumours

4. Routes of Metastasis : Haematogenous Spread : Most common spread in musculoskeletal tumours Lymphatic Spread : rare in musculoskeletal tumours. Seen in Rhabdomyosarcoma , Synovial sarcoma, Malignant fibrous histiocytoma . Direct Implantation : Through surgeons scalpel, needles, sutures, FNAC, diagnostic or excision biopsy Spread through CSF : malignant tumours of ependyma and leptomeninges rarely spread through CSF to vertebrae.

5. Classification of Tumours WHO Classification : widely accepted and is based on histogenesis and histological criteria. 2. Classification based on origin of tumours 3. Classification based on site of lesions.

6. Modified WHO Classification of BONE TUMOURS 1. Bone forming tumours : Benign : Osteoma Osteoid Osteoma Osteoblastoma Intermediate Aggressive Osteoblastoma Malignant Osteosarcoma Conventional osteosarcoma Telangiectatic osteosarcoma Juxta cortical or Parosteal Osteosarcoma Periosteal Osteosarcoma

7. 2. Cartilage forming Tumours BENIGN : Chondroma Enchondroma Osteochondroma Chondroblastoma Chondromyxoid fibroma MALIGNANT : Chondrosarcoma Juxtacortical chondrosarcoma Mesenchymal chondrosarcoma Clear cell chondrosarcoma De differentiated chondrosarcoma Malignant chondroblastoma

8. 3. Giant Cell Tumours : Osteoclastoma Malignant giant cell tumour Giant cell tumour in Pagets disease GCT occurring in non epithelial region Giant cell variants : tumors which histologically show the osteoclastic giant cells  1 - aneurysmal bone cyst 2- osteoclastoma 3- chondroblastoma 4- unicameral bone cyst 5- chondromyxoid fibroma 6- non osteogenic fibroma 7- fibrous dysplasia 8- brown tumor of hyperparathyroidism .

9. 4. Marrow tumours Ewing sarcoma Reticulosarcoma Lymphosarcoma Myeloma

10. 5. Vascular Tumours Benign : Haemangioma Lymphangioma Glomus Tumour Intermediate or inderminate variant : Haemangio endothelioma Hemangio pericytoma Malignant : Angiosarcoma Malignant haemangio pericytoma

11. 6. Other Connective tissue tumours Benign : Benign fibrous histiocytoma Lipoma Intermediate : Desmoplastic fibroma Malignant : Fibrosarcoma Liposarcoma Malignant mesenchymoma Malignant fibrous histiocytoma Leiomyosarcoma Undifferentiated sarcoma

12. 7. Other Tumours Chordoma Adamantinoma Neurilemmoma Neurofibroma 8. Unclassified Tumours

13. 9. Tumour Like Lesions Solitary Bone cysts Aneurysmal bone cyst Juxta articular bone cyst (Intra osseous ganglion) Metaphilic fibrous defect ( non ossifying fibroma ) Eosinophilic granuloma Fibrous dysplasia Myositis ossificans Brown Tumour or hyperparathyroidism Intraosseous epidermoid cyst Giant cell granuloma

14. Classification based on origin of tumours Primary Bone tumours : Derived from bone Metastatic bone Tumours : Due to Mets from : –Breast Lytic + Blastic lesions -Kidney Lytic –Prostate Blastic - Adrenal Lytic –Thyroid Lytic - Intenstine Lytic - Lung, Liver Lytic - Urinary Bladder, Uterine Cervix Lytic lesions 3. Tumour Like Lesions : Non neoplastic Conditions that resemble tumours. Eg : Solitary Bone cyst, Aneurysmal Bone cyst, Fibrous Dysplasia, Brown`s tumour.

15. Classification based on site of Origin Epiphyseal Osteoclastoma , Chondroblastoma Metaphyseal Osteioid osteoma , Osteochondroma , Osteoblastoma , Bone cysts, Osteogenic Sarcoma Diaphyseal Ewing`s sarcoma, Multiple myeloma

16. General Concepts in Tumour Terminology True Capsule : Surrounds a benign lesion and is composed of compressed normal cells and mature fibrous tissue. Pseudocapsule : Compressed tumour cells. Fibrovascular zone of reactive tissue with an inflamamtory component that interdigitates with normal tissue and contains satellite lesions.

17. Compartment : It refers to bone or muscle of origin; For Muscle, compartment is that within its Fascia. For Bone : Intracompartmental implies Bone tumour within the cortex Extracompartmental implies a bone tumour that destroys the cortex and spreads in to the surrouding tissue.

18. Skip Metastasis : A skip metastasis, is defined as a tumor nodule that is located within the same bone as the main tumor or on the opposing side of joint but not in continuity with it. High grade sarcomas have the ability to break through the pseudo capsule and metastasize within the same compartment. MRI Scan better identifies them.

19. Satellite lesion Tumour nodule within reactive zone. Intra Osseous Skip Mets : Embolization of tumour cells within the marrow sinusoids. Transarticular Skip Mets : Occur via periarticular venous anastamosis – Very poor prognosis

20. GRADING and STAGING of TUMOURS To determine prognosis and choice of treatment. GRADING : It is defined as macroscopic and microscopic degree of differentiation of tumour BORDER`s GRADING : GRADE I : Well differentiated; <25% Anaplastic cells GRADE II : Moderately Differentiated; 25-50% Anaplastic cells GRADE III : Moderately differentiated; 50-75% Anaplastic cells GRADE IV: Poorly differentiated; >75% Anaplastic cells

21. Enneking`s Grading of Tumours G0    Histologically benign (well differentiated and low cell to matrix ratio) G1    Low grade malignant (few mitoses, moderate differentiation and local spread only); Have low risk of metastases G2    High grade malignancy (frequent mitoses, poorly differentiated); High risk of metastases

22. STAGING OF TUMOURS STAGING is defined as extent of spread of tumour. It is determined by clinical examination, Investigations and pathological studies. Common staging systems are ENNEKING `S STAGING SYSTEM AJCC SYSTEM TNM STAGING ( Union International Cancer centre Geneva Staging System )

23. ENNEKING`s STAGING OF BENIGN TUMOURS Latent —low biological activity; well marginated ; remains static or heals spontaneously; often incidental findings (i.e., nonossifying fibroma ) 2. Active —symptomatic; limited bone destruction; progressive growth but limited by natural barriers; may present with pathological fracture (i.e., aneurysmal bone cyst) 3. Aggressive —aggressive; bone destruction/soft tissue extension; do not respect natural barriers (i.e., giant cell tumor )

24. GTM classification described by Enneking is adopted by Musculoskeletal Tumour society and is based on surgical grading (G), location (T), lymphnode involvement & metastasis (M) Enneking`s staging of malignant tumours STAGE GRADE SITE I A Low – G1 Intracompartmental T1 I B Low – G1 Extracompartmental T2 II A High G2 Intracompartmental T1 II B High G2 Extracompartmental T2 III A Any grade with regional or distal Metastases Intracompartmental T1 III B Any grade with regional or distal Metastases Extracompartmental T2

25. American joint committee on cancer system bone sarcoma classification (AJCC Classification) The AJCC system for bone sarcomas is based on tumor grade, size, and presence and location of metastases.

26. TNM STAGING (Union International Cancer centre Geneva Staging System) T – Primary Tumour – T to T 4 In Situ lesion T to largest and most extensive T 4 primary tumour N – Nodal involvement – N to N 3 No lymph nodes involvement N to wide spread nodal involvement N 3 M – Metastasis – M to M 2 No Metastasis M to distant metastasis M 2

27. CLINICAL PRESENTATION Pain : Initially may be activity related, but in case of malignancy there could be progressive pain at rest and at night. In benign tumours, pain may be activity related when it is large enough to compress surrounding soft tissue or when it weakens bone. A benign Osteioid osteoma may cause night pain initially that classically gets relieved with Aspirin.

28. In case of soft tissue sarcomas patients may come with mass rather than pain but in some exceptions like nerve sheath tumours, they have pain and neurological conditions. Age : It is the most important denominator because most musculoskeletal tumours occur within specific age ranges. Sex : Very few tumours show sex prediliction . Eg GCT is commoner in females. Family History : may be present in tumours like exostosis / von recklenghausen`s disease.

29. INVESTIGATIONS Serological investigations : 1. Complete Blood Picture : Haemoglobin : to rule out anaemia that may be due to replacement of bone marrow by neoplastic process. ESR : raised in mets , Ewing`s sarcoma, lymphoma, leukemias 2. Increased Prostate Specific Antigens (PSA) with Prostatic Acid Phosphatase levels in a case of blastic lesions of x ray is the diganostic of Mets secondary to Prostate Carcinoma .

30. 3. Serum alkaline phosphatase (ALP) Biological marker of tumour activity. Increases significantly when tumour and metastasis are highly osteogenic . ALP levels decline after Surgical removal of primary tumour and elevates if metastasis aggravates. Good prognostic tool. Increased in following conditions: - Osteoblastic bone tumors (metastatic or osteogenic sarcoma) 5-Nucleotidase and GGT ( Gamma glutamyl Trasferase ) are elevated in liver pathology along with Alkaline phosphatase , where as in bone pathologies only ALP is increased.

31. 4. Antisarcoma Antibodies : Monoclonal antibodies can be detected by immunohistochemical assays. Antibodies binding to sarcoma cell surface antigens have specificity. 5. Osteocalcin – A : Helpful in diagnosing heavily bone producing types of tumours . 6. Serum Calcium : Hypercalcemia is often due to Mets, Myeloma, Hyperparathyroidism. 7. Abnormal Serum protein electrophoresis along with bence jones proteins in urine is classical of Multiple myeloma

32. Flow Cytometry A sample of cells are treated with special antibodies that stick to the cells only if certain substances are present on their surfaces. The cells are then passed in front of a laser beam. If the cells now have antibodies attached to them, the laser will cause them to give off light, which can be measured and analyzed by a computer. Flow cytometry can help determine type of those abnormal cells and help in diagnosing a tumour early.

33. INVESTIGATIONS: RADIOGRAPHS Phemister's Law = the most common site of infection & tumours is the fastest growing site of the long bone To see a lucent lesion in bone, an estimated 30 to 50 % of the bone must first be lost [ Harris & Heaney, N Engl J Med 1969 ]

34. Radiographic Evaluation Five important parameters in evaluating a tumour on a X RAY are Anatomic site Borders Bone destruction New Matrix ( Bone) formation Periosteal reaction

35. A. Anatomic Sites – X ray Anatomic site Specific anatomic sites of the bone give rise to specific groups of lesions .

36. Characteristic Locations Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, clivus Osteoblastoma Spine, posterior

37. Characteristic Locations Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, clivus Osteoblastoma Spine, posterior

38. Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, clivus Osteoblastoma Spine, posterior Characteristic Locations

39. Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, clivus Osteoblastoma Spine, posterior Characteristic Locations

40. Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, Pelvis Osteoblastoma Spine, posterior Characteristic Locations

41. Simple bone cyst Proximal humerus Chondroblastoma Epiphyses Giant Cell tumor Epiphyses Adamantinoma Tibia Chordoma Sacrum, clivus Osteoblastoma Spine - posterior elements Characteristic Locations

42. B. Borders The border reflects the growth rate and the response of the adjacent normal bone to the tumor. Most tumors have a characteristic border Benign lesions (e.g., nonossifying fibromas and unicameral bone cysts) have well-defined borders and a narrow transition area that is often associated with a reactive sclerosis. Aggressive or benign tumors (e.g., chondroblastoma and GCTs) tend to have faint borders and wide zones of transition with very little sclerosis , reflecting a faster-growing lesion. Poorly delineated or absent margins indicate an aggressive or malignant lesion

43. C. Bone destruction Bone destruction is the hallmark of a bone tumor. Three patterns of bone destruction are described Geographic , Moth-eaten , Permeative .

44. Geographic Bone Destruction Complete destruction of bone from boundary to normal bone Non-ossifying fibroma Chondromyxoid fibroma Eosinophilic granuloma Non-ossifying fibroma

45. Moth-eaten Bone Destruction Areas of destruction with ragged borders Implies more rapid growth Probably a malignancy Examples: Myeloma Metastases Lymphoma Ewing’s sarcoma Multiple Myeloma

46. Permeative Bone Destruction Ill-defined lesion with multiple “worm-holes” Spreads through marrow space Wide transition zone Implies an aggressive malignancy Round-cell lesions Examples: Lymphoma, leukemia Ewing’s Sarcoma Myeloma Osteomyelitis Neuroblastoma Leukemia

47. Patterns of Bone Destruction Geographic Moth-eaten Permeative Less malignant More malignant

48. D. Matrix formation Calcification of the matrix, or new bone formation, may produce an area of increased density within the lesion . Calcification typically appears as flocculent or stippled rings or clusters. The appearance of the new bone varies from dense sclerosis that obliterates all evidence of normal trabeculae to small, irregular, circumscribed masses described as "wool" or "clouds." Calcification and ossification may appear in the same lesion. Neither type of matrix formation is diagnostic of malignancy.

49. Tumor Matrix Osteoblastic Fluffy, cotton-like or cloud-like densities Osteosarcoma

50. Cartilaginous : Comma-shaped, punctate , annular, popcorn-like as Enchondroma , chondrosarcoma , chondromyxoid fibroma Tumor Matrix Chondrosarcoma

51. Expansile Lesions of Bone Multiple myeloma Mets Brown tumor Enchondroma Aneurysmal bone cyst Fibrous dysplasia

52. Multiple myeloma Mets Brown tumor Enchondroma Aneurysmal bone cyst Fibrous dysplasia Expansile Lesions of Bone Renal cell carcinoma

53. Multiple myeloma Mets Brown tumor Enchondroma Aneurysmal bone cyst Fibrous dysplasia Expansile Lesions of Bone

54. Multiple myeloma Mets Brown tumor Enchondroma Aneurysmal bone cyst Fibrous dysplasia Expansile Lesions of Bone

55. E. Periosteal reaction Periosteal reaction is indicative of malignancy but not pathognomonic of a particular tumor . Any widening or irregularity of bone contour may be regarded as periosteal activity.

56. Solid Periosteal Reactions Chronic osteomyelitis Single solid layer or multiple closely apposed and fused layers of new bone attached to the outer surface of cortex resulting in cortical thickening. It is uniterrupted or continous .

57. Types of Solid Periosteal Reaction 1. SOLID BUTTRESS Seen in Aneurysmal bone cyst, chondromyxoid fibroma 2. Solid Smooth or Elleptical layer Seen in Osteoid osteoma and osteoblastoma 3. Undulating type : Seen in long standing varicosities, periosteitis , chronic lymphaoedema . 4. Single Lamellar reaction : Seen in Osteomyelitis , Stress Fractures, Langerhans cell histiocytosis .

58. Interupted Periosteal Reactions Commonly seen in Aggressive/malignant tumours . Onion-Peel ( lamellated ) Ewings sarcoma Gouchers disease Sunburst Codman’s triangle Ewing sarcoma

59. Sunburst type of periosteal reaction Fine lines of increased density representing newly formed specules of bone radiate laterally from and at right angles to the surface of the shaft giving a typical sun ray appearance. Osteo-sarcoma

60. Codman’s triangle When the tumour breaks through the cortex and destroys the newly formed lamellated bone, the remnants of the latter on both ends of the break through area may remain as a triangular structure known as codman triangle. Also seen in Osteosarcoma , Ewings sarcoma, Chronic Osteomyelitis Osteo -sarcoma

61. Periosteal Reactions Solid onion-peel Sunburst Codman’s triangle Less malignant More malignant

62. Radiographic Features in a Benign vs. Malignant

63. Mnemonic for Luscent bone lesions = FOGMACHINES   F ibrous Dysplasia O steoblastoma G iant Cell Tumour M etastasis/ Myeloma A neurysmal Bone Cyst C hondroblastoma / Chondromyxoid Fibroma H yperparathyroidism (brown tumour)/ H aemangioma I nfection N on-ossifying Fibroma E osinophilic Granuloma / Enchondroma S imple Bone Cyst

64. It delineates intra and extra osseous extent of tumour . It can reliably distinguish between infection and tumor. CT scan identifies accurately area of cortical break through, soft tissue extension, medullary spread and proximity of the tumour to neurovascular bundle and evaluating integrity of cortex To differentiate solid and cystic lesions. Most sensitive investigation to detect Pulmonary mets . CT scan:-

65. Best imaging to localise the nidus of an osteiod osteoma , to detect a thin rim of reactive bone around an aneurysmal bone cyst, to evluate calcification in a suspected cartilagenous lesion and to evaluate endosteal cortical erosion in a suspected chodrosarcoma . To differentiate between the neoplastic mass and inflammatory condition : Neoplastic masses displace soft tissue fat planes where as they are obliterated in inflammatory conditions. It cannot differentiate benign from malignant tumours accurately. Except in detecting pulmonary mets , Contrast CT is better than plain CT.

66. It has better contrast discrimination than any other modality. Helps in detecting skip lesions Assesses the tumor relationship with adjacent soft tissue, joints and blood vessels. It can visualize bone marrow content and demonstrate intramedullary extension of neoplasm. MRI:-

67. It is the investigation of choice in local staging of musculoskeletal tumours. On MRI, it is not possible to accurately differentiate benign from malignant tumours. But if the following criteria are present, lesion can be considered as a malignant one : 1. Mass with irregular Border 2. Non homogenous signal intensity with extra compartmental extension 3. Peri tumoral edematous reaction. 4. Soft tissue mass situated deep to fascia and measuring more than 5 cm in greatest diameter is likely to be a sarcoma.

68. It uses radioactive glucose to locate cancer by observing high glycolysis rates in a malignant tissue metabolism. It has low specificity as the FDG ( Fluoro labelled deoxy glucose) can also accumulate in benign aggressive and inflammatory lesions. Also helpful in evaluating the tumour after chemotherapy . Micromets are better visulaised . PET- Positron Emission Tomography

69. Most reliable means of determining vascular anatomy. Reactive zone is best seen on early arterial phase, while the intrinsic vascularity is best seen on late venous phase as a tumour blush. Transcatheter embolisation is done as a definitive treatment in some benign vascular tumours . Angiography

70. Angiography demonstrating vascularity of a tumour Embolization of a vascular lesion, performed at least 6 hours prior to surgery, is expected to significantly reduce intraoperative blood loss.

71. Technetium ( 99 mTC) bone scans are used. It is an indicator for mineral turnover. Whenever there is altered local metabolism in remodeling bone, increased vascularity or mineralization , the isotope uptake is enhanced mainly in reactive zone surrounding the lesions. Confirms epiphyseal spread of tumour . Helps in detecting multiple lesions like multiple osteochondroma , enchondroma . Where as a MRI helps in detecting skip lesions Nuclear Imaging -Bone scan Scinitigraphy

72. Bone scan showing HOT SPOTS over proximal humerus and ribs It detects the presence of skeletal metastasis and delineates it from primary else where in the body.

73. Bone scinitigraphy tends to show larger area of extension of medullary involvement of tumour as the radio active agent also localises the area of hyperemia and edema adjacent to tumour. Nuclear imaging is advantageous only to identifying whether skeletal involvement is solitary or multiple.

74. Not routinely used in diagnosis of sarcoma; as it better differentiates only bony cystic lesions. However Ultrasound is used in guided percutaneous biopsy. In patients treated with prosthetic implants, USG is the modality that depicts early recurrence as MRI produces blurred and artifact images due to metallic implants. Ultrasound

75. Used for definitive diagnosis. Principles of biopsy: Opted only after all other investigations are performed. A biopsy can be done by FNAC, core needle biopsy, or an open incisional procedure. FNAC may be 90% accurate at determining malignancy; however, its accuracy at determining specific tumor type is much lower. Trephine or core biopsy is recommended and often yields an adequate sample for diagnosis. Complications are greater with incisional biopsy ; but least likely to be associated with a sampling error, and provides the sample for additional diagnostic studies, such as cytogenetics and flow cytometry . Biopsy

76. Core biopsy is preferred if limb spraying is an option as it entails less contamination than open biopsy. A small incisional biopsy can be performed if core biopsy specimen is inadequate. Performed under torniquet (possibly) - the limb may be elevated before inflation but should not be exsanguinated by compression bandage. Longitudinal incisions preferred as transverse excision are extremely difficult or impossible to excise with the specimen. NV bundle not exposed. Dissection through muscle (not between) to prevent contamination of tumour.

77. Approach for open biopsy is made through region of definitive surgical excision. If a drain is used, it should exit in line with the incision so that the drain track also can be easily excised en bloc with the tumor . Wound is closed tightly in layers . Meticulous haemostasis is arrested by use of bone wax/ Poly Methyl Metha Acrylate (PMMA) to plug the cortical window . Always sample the tissues from periphery of lesion which contains most viable tissue. Never biopsy a periosteal reaction / codmans traingle as it contains a new reactive bone and could be false negative.

78. If hole must be made in bone during biopsy, defect should be round or oval to minimize stress concentration , which otherwise could lead to pathological fracture. Torsional strength is not affected by length of defect. Always attempt to keep defects less than 10% of bone diameter. When biopsy size is greater than 20% of bone diameter, torsional strength decreases to 50 %.

79. Examples of poorly performed biopsies Biopsy resulted in irregular defect in bone, which led to pathological fracture

80. Examples of poorly performed biopsies Transverse incisions should not be used Needle biopsy track contaminated patellar tendon Multiple needle tracks contaminate quadriceps tendon

81. Drain site was not placed in line with incision Needle track placed posteriorly , location that would be extremely difficult to resect en bloc with tumor if it had proved to be sarcoma

82. Biopsy should be done only after clinical, laboratory, and radiographic examinations are complete. Completion of the evaluation before biopsy aids in planning the placement of the biopsy incision, helps provide more information leading to a more accurate pathological diagnosis, and avoids artifacts on imaging studies. If the results of the evaluation suggest that a primary malignancy is in the differential diagnosis, Biopsy is not done unless it is possible to operate the case in the centre.

83. Curettage resection and restoration of function by limb salvage procedures or amputation is primary form of surgical correction. Based on surgical plane of dissection in relation to tumour , Enneking formulated following types of resection. Intralesional Resection Marginal resection Wide ( Intracompartmental ) resection Radical ( Extracompartmental ) resection SURGICAL OPTIONS

84. An intralesional margin is one in which the plane of surgical dissection is within the tumor . This type of procedure is often described as “ debulking ” because it leaves behind gross residual tumor . This procedure may be appropriate for symptomatic benign lesions when the only surgical alternative would be to sacrifice important anatomical structures. This also may be appropriate as a palliative procedure in the setting of metastatic disease. Intralesional resection is through the psuedocapsule of the tumor directly in to the lesion. Macroscopic tumour is left behind. Curettage is intralesional proceedure . 1) Intralesional Resection :

85. CURETTAGE Cortical window with rounded margins is made When possible, the window is sized larger than the tumour so that the entire tumour is readily seen . The rounded margins reduce the risk of subsequent fracture. Large curetts should be used to remove the lesional tissue. Tumour margin should be treated with cryotherapy , PMMA cementage or phenol – alcohol cauterisation , argon beam coagulation in case of aggressive tumours . If curettage weakens the bone, graft using allograft or autograft with or with out internal fixation is indicated.

86. A marginal margin is achieved when the closest plane of dissection passes through the pseudocapsule . This type of margin usually is adequate to treat most benign lesions and some low-grade malignancies. In high-grade malignancy, however, the pseudocapsule often contains microscopic foci of disease, or “satellite” lesions. A marginal resection often leaves behind microscopic disease that may lead to local recurrence if the remaining tumor cells do not respond to adjuvant chemotherapy or radiation therapy. 2) Marginal Resection

87. Intracompartmental Wide margins are achieved when the plane of dissection is in normal tissue. Although no specific distance is defined, the Resection includes removal of entire tumour , + Reactive zone & cuff of normal tissue. If the plane of dissection touches the pseudocapsule at any point, the margin should be defined as being marginal and not wide. Although sometimes impossible to achieve, wide margins are the goal of most procedures for high-grade malignancies. 3) Wide Resection

88. 4] Radical Radical margins are achieved when all the compartments that contain entire tumor and structure or origin of lesion are removed en bloc. The plane of dissection is beyond the limiting fascial & bone borders. For deep soft-tissue tumors , this involves removing the entire compartment (or multiple compartments) of any involved muscles. However, with improvements in imaging studies, radical procedures now are rarely performed because equivalent oncological results usually can be obtained with wide margins .

89. ENNEKING`s Classification of Surgical Procedures for Bone Tumors Margin Local (Mode of resection) LIMB SALVAGE OPTIONS Amputation(Mode of amputation) Intralesional Curettage or debulking Debulking amputation Marginal Marginal excision Marginal amputation Wide Wide local excision Wide through bone, amputation Radical Radical local resection Radical disarticulation

90. Enneking`s Classification of Resection of tumours.

91. 1] Limb Salvage Proceedures 2] Amputations SURGICAL OPTIONS

92. It is designed to accomplish removal of a malignant tumour & reconstruction of the limb with an acceptable oncologic, functional & cosmetic result. It is sub amputative wide resection with preservation of the limb & its function. Indications : Stage IA Stage IIA & Stage IIIA (All intracompartmental tumours )with good response to pre-operative chemotherapy Skin should be uninvolved and free There should be feasibility of keeping a cuff of normal tissue surrounding the tumour Upper extremity lesions are more suitable for limb sparing surgery Tumours with good pre-operative chemotherapy response LIMB SALVAGE PROCEDURES

93. Reconstruction of bone defect may be done by 1] Osteoarticular allograft reconstruction 2] Allograft-prosthesis composite reconstruction 3] Endoprosthetic reconstruction. 4] Allograft arthrodesis 5} Rotationplasty 6} Turnoplasty Surgical reconstructive options :

94. Amputation provides definitive surgical treatment when limb sparing is not a prudent one. Common amputations in malignant tumours : Proximal humerus : fore quarter amputation Distal femur : hip disarticulation Proximal tibia : mid thigh amputation AMPUTATIONS

95. Ennekings Classification of Amputations

96. Adjuvant chemotherapy: To treat presumed micrometastasis Neo adjuvant[induction] Before surgical resection of the primary tumour Advantages: It controls micro metastasis and improves survival rate. Chemotherapy makes limb salvage surgery easier. Decreases tumor size and vascularity . The response to Chemotherapy can be evaluated after surgery. Chemotherapy

97. With Megavoltage radiotherapy tumor cell can be destroyed. High voltages are administered in short sessions. Radiation therapy should be started immediately after diagnosis before surgery to prevent metastasis . Chemotherapy increases the susceptibility of tissues to irradaition . Protect all normal tissue biopsy scars to prevent radiation necrosis. Distribute the dose in accordance with distribution of tumor. RADIOTHERAPY

98. Diagnosis Neoadjuvant chemotherapy + Radiation Resection/ surgery Repeat Chemo + Radiation Adjuvant + irradiation +chemo Histological Grading SEQUENCE OF TREATMENT

99. Gene therapy in sarcomas : Targeting Osteocalcin promoter. Osteocalcin is produced both in Osteoblastic [100%]and fibroblastic[70%] Osteosarcoma . LIQUID BRACHYTHERAPY : Injecting Intra arterial infusion of chemotherapeutic drugs with brachytherapy It is in Phase 2 trials currently. Cryotherapy is used in curettage after resection of primary tumour to prevent chances of recurrence. PMMA, Phenol, liquid nitorgen commonly used cryoprecipitates . RECENT ADVANCES

100. Oncologist BoneTumours Diagnosis Treatment Radiologist Cytopathologist Surgeon Histopathologist Molecular Pathologist Geneticist psychiatrist Nursing And Support staff Audit MUSCULOSKELETAL TUMOURS are Evolving in to a multi disciplinary approach

101. OSTEOCHONDROMA Osteochondroma is a bony exostosis projecting from the external surface of a bone. It is usually has a hyaline lined cartilaginous cap The cortex and spongiosa of the lesion merge with that of the host bone

102. When the lesion is seen in a single bone , it is called solitary osteochondroma If two or three bones are involved , with no familial history , the condition is known as multiple ostechondromas Widespread ostechondromas are associated with a positive familial history, and the condition is known as Heriditary Multiple Exostosis

103. INCIDENCE Most common skeletal growth/tumor Approximate incidence is 50% of all benign bone tumors Male : Female ratio 2:1 Most are encountered in childhood and adolescence 75% occur before the age of 20 Many cases may not be diagnosed due to the silent nature of the disease

104. PATHOPHYSIOLOGY Developmental lesions rather than true neoplasms . These lesions result from the separation of a fragment of epiphyseal growth plate cartilage, which subsequently herniates through the periosteal bone cuff . The mechanism likely results from the remodeling during growth of the long bone. Persistent growth of this cartilaginous fragment and its subsequent enchondral ossification (maturation) result in a subperiosteal osseous excrescence with a cartilage cap that projects from the bone surface. After adolescence and skeletal maturity, osteochondromas usually exhibit no further growth.

105. The development of an osteochondroma , beginning with an outgrowth from the epiphyseal cartilage Histology: Covered by thin layer of periosteum . Binucleate chondrocytes in lacunae. Contains hyaline cartilage , bony tissue and normal bone marrow particle .

106. LOCATION

107. UNCOMMON SITES Metacarpals Condylar process of the mandible Base of the skull Talus Calcaneus Spine Distal end of the clavicle( can cause rotator cuff syndrome)

108. TYPES

109. Sessile Variant Creates a broad based exostosis lacking an elongated projection Causes a long asymmetric elongation of the bone Amorphous , spotty calcification is absent Occur at the metaphyseal – diaphyseal region

110. Pedunculated Variant Knee is the most common location (tibia and fibula) Metaphysis is the common site of involvement Lesion has a slender stalk with a cartilaginous dome The cartilage may show dense amorphous / spotty calcification

111. CLINICAL FEATURES Most are asymptomatic Symptoms arise as a result of their Location Size Pressure effects on adjacent structures Tendon or nerve irritation Usual complaint is hard palpable mass

112. COMPLICATIONS

113. MALIGNANT TRANSFORMATION Presents with Growth of lesion after skeletal maturity Pelvis / shoulder (mostly sessile variety) < 1 % in solitary , > 10% in HME Increasing mass and pain at the site of lesion in absence of fracture, bursitis or nerve compression Radiologically Bone destruction Dispersed calcification in cartilaginous cap Soft tissue mass

114. X RAY - Pedunculated Lateral radiograph of a pedunculated osteochondroma of the distal femur. COAT HANGER EXOSTOSIS : The lesion invariably point away from the joint due to muscle pull

115. X RAY Sessile Lateral radiograph of a sessile osteochondroma of the distal femur.

116. USG Ultrasonography can be applied to analyze the cartilaginous cap of an osteochondroma . Ultrasonography is also valuable in the diagnosis of bursitis and other complications associated with osteochondromas , such as arterial or venous thrombosis, as well as aneurysm and pseudoaneurysm formation .

117. CT SCAN Allows optimal demonstration of the pathognomonic cortical and medullary continuity of the lesion and parent bone . Mineralization in the cartilage cap allows a correct CT measurement .  Cartilage cap thickness greater than 2 cm in adults and 3 cm in growing children suggests malignant transformation .

118. MRI MRI is useful for assessing the continuity of the parent bone with the cortical and medullary bone in an osteochondroma . MRI also provides information about inflammation in reactive bursa formation, impingement syndromes, and arterial and venous compromise. This study is the method of choice for evaluating compression of the spinal cord, nerve roots, and peripheral nerves.

119. TREATMENT No treatment necessary for asymptomatic osteochondromas (Observation) . If the lesion is causing pain or neurologic symptoms due to compression, it should be Excised None of the cartilage cap or perichondrium should be left in the resection bed or recurrence can occur. Patients with many large osteochondromas should have regular radiographic screening exams for the early detection of malignant transformation In adults if the osteochondroma has recently become bigger, then urgent surgery is done due to fear of malignancy

120. HEREDITARY MULTIPLE EXOSTOSES Autosomal dominant condition Mutations in the  EXT1  and  EXT2  genes cause hereditary multiple exostoses Multiple osteochondromas Asymmetric growth at the knees and ankles and Short stature Malignant transformation rates as high as 25%

121. ENCHONDROMA Enchondromas  (or  chondromas   ) are a relatively common benign medullary cartilaginous neoplasm with benign imaging features.

122. EPIDEMIOLOGY Enchondromas are most frequently diagnosed in childhood to early adulthood with a peak incidence of 10-30 years. They account for ~5% (range 3-10%) of all bone tumours  and ~17.5% (range 12-24%) of benign bone tumours .

123. CLINICAL FEATURES Mostly, they are an incidental finding.  They are usually asymptomatic, but may be complicated by a pathological fracture or malignant transformation into a low-grade  chondrosarcoma . The latter is rare. It is important to note that if an enchondroma is painful in the absence of a fracture, it should be considered malignant.

124. PATHOLOGY Enchondromas arise from rests of growth plate cartilage/ chondrocytes that subsequently proliferate and slowly enlarge and are composed of mature hyaline cartilage. Hence, they are seen in any bone formed from cartilage. Lesions are usually <3 cm, translucent, nodular, and are grossly grey-blue.

125. ASSOCIATIONS Two syndromes are associated with multiple enchondromas : Ollier disease Maffucci syndrome

126. LOCATION Almost all enchondromas are located centrally within the medullary cavity of tubular bones. The typical distribution is: Small tubular bones of the hands and feet: 50%  Large tubular bones, e.g. femur, tibia, humerus Rarely an enchondroma may extend through the cortex and demonstrate an exophytic growth pattern. This is known as an  Enchondroma Protuberans , and may either be seen sporadically or as part of  Ollier disease.

127. RADIOGRAPHIC FEATURES When located in the phalanges, enchondromas are expansile and are usually purely lytic . In other locations,  enchondromas are expansile , with characteristic “rings and arcs” calcifications.  Typically, enchondromas are small 1-2 cm  lytic lesions with non-aggressive features: narrow zone of transition sharply defined scalloped margins: may have mild  endosteal scalloping expansion of the overlying cortex may be present, but there should not be cortical breakthrough unless fractured chondroid calcifications may be present: rings and arcs calcification no periosteal reaction no soft tissue mass

128. The majority of enchondromas more frequently arise in the metaphyseal region, owing presumably to their origin from the growth plate , although they are frequently seen in the diaphysis . They only rarely are seen in the epiphysis, and a cartilaginous lesion in an epiphysis is more likely to be a chondrosarcoma  .

129. MRI is useful in evaluating for soft tissue extension and for confirming the diagnosis. Enchondromas appear as well circumscribed somewhat lobulated masses replacing marrow. Nuclear medicine - Increased uptake on the bone scan can be seen with enchondromas . Intense uptake occurs with underlying pathological fracture or cortical expansion in small bones .

130. COMPLICATIONS Pathological fractures Malignant transformation into chondrosarcomas

131. TREATMENT The majority of enchondromas remain asymptomatic and require no treatment.  In the setting of a fracture, the bone may be allowed to heal. If necessary, a curettage and bone grafting can be performed at a later time. If malignant transformation is suspected, which occurs in less than 5% of cases, then treatment is more aggressive .