CLASSIFICATION OF BONE TUMORS & PRINCIPLES OF LIMB.pptx

Classification of bone tumours

1. CLASSIFICATION OF BONE TUMORS & PRINCIPLES OF LIMB SALVAGE SURGERY Dr Sanjay K Junior resident Orthopaedics KMCT Medical College

2. Tumours of bone and soft tissue classified on the basis of their principle cell type, and have been classified by the WHO. Tissue diagnosis essential to predict the natural history and treatment of the lesion.

3. BENIGN LESION OF BONE one that does not invade surrounding tissue or spread elsewhere in the body. limited capacity for recurrence Recurrence occurs in a non-destructive manner. Surgical resection is often curative

4. wide variety of behaviours : latent or inactive (e.g. non ossifying fibroma ), active, with a higher risk of recurrence after treatment (e.g.  aneurysmal bone cyst ).

5. INTERMEDIATE (LOCALLY AGGRESSIVE) LESIONS OF BONE can destroy bone and surrounding tissue (e.g.  osteoblastoma ). often recur and are associated with an infiltrative and locally destructive growth pattern. Recurrence is frequent following limited surgical treatment sometimes en bloc resection is required to completely remove the lesion.

6. INTERMEDIATE (RARELY METASTASIZING) LESIONS often behave in a similar way to locally aggressive lesions but occasionally demonstrate the ability to spread to distant sites The risk of such spread is <2% Eg : Giant cell tumor of bone

7. MALIGNANT TUMOURS truly aggressive with the potential for both local extension and metastases to distant sites. The aggressiveness of a tumour is defined by the histological grade. : low grade & high grade Low-grade tumours (e.g. chordoma and parosteal osteosarcoma ) : slow rate of growth and metastases are less common but can arise many years after initial diagnosis.

8. High-grade  tumours : very high risk of metastasizing, ranging from 20% to 100%, and are locally invasive (e.g. osteosarcoma and Ewing’s sarcoma ). Some histologically low-grade lesions have a metastatic rate of only 2–10%, though they may acquire a higher grade at the time of local recurrence and so a higher risk of metastasizing (e.g.   chondrosarcoma ).

9. ENNEKING CLASSIFICATION

10. classification of tumours of bone (based on the World Health Organization (WHO) histological classification of tumours ) - 2020

11. Benign Intermediate Malignant 1. Osteogenic tumours Osteoma NOS Osteoid osteoma NOS Osteoblastoma NOS Low-grade central osteosarcoma Osteosarcoma NOS Parosteal osteosarcoma Periosteal osteosarcoma High-grade surface osteosarcoma Secondary osteosarcoma 2. Chondrogenic tumours Subungual exostosis Bizarre parosteal osteochondromatous proliferation. Periosteal chondroma Enchondroma Osteochondroma Chondroblastoma NOS Chondromyxoid fibroma Osteochondromyxoma Chondromatosis NOS Atypical cartilaginous tumor Chondrosarcoma , grades 1 Chondrosarcoma , grades 2 Chondrosarcoma , grades 3 Periosteal chondrosarcoma Clear cell chondrosarcoma Mesenchymal chondrosarcoma Dedifferentiated chondrosarcoma 3. Fibrogenic tumours Desmoplastic fibroma Fibro sarcoma NOS 4. Giant cell-rich tumours Aneurysmal bone cyst Non-ossifying fibroma Giant-cell tumour NOS Malignant giant-cell tumour 5. Notochordal tumours Benign notochordal tumour Chordoma NOS ( Chondroid chordoma ) Dedifferentiated chordoma Poorly differentiated chordoma

12. 8. Hematopoietic neoplasms of bone Plasmacytoma of bone Hodgkin disease NOS Malignant lymphoma, non-Hodgkin, NOS; Diffuse large B-cell lymphoma NOS; Follicular lymphoma NOS; Marginal zone B-cell lymphoma NOS; T-cell lymphoma NOS; Anaplastic large cell lymphoma NOS; Malignant lymphoma, lymphoblastic, NOS: Burkitt lymphoma NOS Langerhans cell histiocytosis NOS Langerhans cell histiocytosis , disseminated Erdheim -Chester disease Rosai-Dorfman disease 9. Undifferentiated small round cell sarcomas of bone and soft tissue Ewing sarcoma Round cell sarcoma with EWSR1– nonETS fusions CIC-rearranged sarcoma Sarcoma with BCOR genetic alterations Benign Intermediate Malignant 6. Vascular tumours Haemangioma Epithelioid haemangioma Angiosarcoma Epithelioid haemangioendothelioma 7. Other mesenchymal tumors of bone Chondromesenchymal hamartoma of the chest wall Simple bone cyst Fibrous dysplasia Osteofibrous dysplasia Lipoma NOS Hibernoma Osteofibrous dysplasia-like adamantinoma Mesenchymoma NOS Adamantinoma of long bones (Dedifferentiated adamantinoma ) Leiomyosarcoma NOS Pleomorphic sarcoma, undifferentiated Bone metastases

13. Common locations of bone tumors

14. Possible diagnosis based on the radiographic appearances, divided by age group

15. Osteochondroma - 14 YEAR OLD BOY Sessile or pedunculated lesions SITES : Knee (proximal tibia, distal femur) Proximal femur Proximal humerus Subungal exostoses )

16. ENCHONDROMA - 65 YEAR OLD FEMALE Well defined, lucent, central medullary lesion “pop-corn” stippling, arcs, whorls, rings hands (60%) > feet distal femur > proximal humerus > tibia Associated conditions : Solitary enchondroma Ollier’s disease (multiple enchondramatosis ) Maffucci’s syndrome (multiple enchondramatosis + soft tissue angioma s )

17. PERIOSTEAL CHONDROMA – 22 YEAR OLD FEMALE Well demarcated shallow cortical defect Saucerization of underlying bone Proximal humerus (59%), distal femur and proximal femur metacarpals or phalanges

18. CHONDROBLASTOMA – 18 YEAR OLD MALE Well circumscribed epiphyseal lytic lesion Distal femur and proximal tibia > proximal humerus , proximal femur, calcaneus, flat bones Histology : Chondroblasts arranged in “cobblestone” or “chicken wire pattern”

19. Chondrosarcoma - 76 year old woman Proximal femur, pelvis, proximal humerus , distal femur, scapula and proximal tibia appear as large, intraosseous , osteolytic tumours with a narrow zone of transition and irregular, granular calcifications within the matrix Endosteal scalloping of the cortex and eventual cortical destruction can occur,

20. OSTEOID OSTEOMA an area of dense sclerosis with a small, rounded area of osteolysis which is often obscured by the surrounding sclerosis

21. DESMOPLASTIC FIBROMA - 18 YEAR OLD GIRL most frequently occur in the mandible and pelvis as well as the long bones lytic, expansile lesion within the cortex replaced by a thin shell of new bone

22. NON OSSIFYING FIBROMA - 25 YEAR OLD MALE Nest of fibrous tissue appears within the bone and persists for some years before ossifying metaphyses of long bones

23. GIANT CELL TUMOR – 29 YEAR OLD FEMALE affect the metaphyses of long bones with preponderance for the distal femur, proximal tibia, distal radius and proximal humerus eccentric, expansile , lobulated lytic lesion with a narrow zone of transition.

24. SIMPLE BONE CYST – 10 YEAR OLD BOY proximal humerus , the proximal femur or the proximal tibia, most commonly affecting the metaphyseal areas close to the physis . X-rays demonstrate a welloutlined , Lytic, centrally placed, metadiaphyseal lesion expanding and thinning the cortices

25. ANEURYSMAL BONE CYST (ABC) – 9 year old boy metaphyses of long bones, particularly the femur, tibia and humerus expansile , lytic, cystic lesion

26. Fibrous dysplasia – 73 year old male The craniofacial bones, femur, pelvis, and tibia are commonly involved associated with endocrinopathies , and café-au- lait spots, McCune–Albright syndrome, and with intramuscular myxomas in Mazabraud syndrome. non-aggressive well-circumscribed lesion with a characteristic ground-glass matrix proximal femoral fibrous dysplasia - shepherd’s crook deformity

27. Osteofibrous dysplasia – 15 year old boy typically seen in the anterior cortex of the tibia, particularly in children or teenagers soap bubble appearance.

28. Langerhans cell histiocytosis (LCH) - 8 year old girl Presented with insidious onset of pain in the mid-thoracic spine demonstrate vertebra plana at the level of T6.

29. osteoblastoma Osteoblastoma of olecranaon demonstrates a lytic lesion, typically 2–5 cm in size

30. osteosarcoma Codman’s triangle where new bone forms in response to periosteal elevation ‘sunburst’ appearance when the periosteum does not have enough time to lay down a new layer and instead the Sharpey’s fibres stretch perpendicular to the periosteum Metaphyseal or metadiaphyseal , Distal femur, proximal tibia, proximal femur and humerus

31. Ewing’s sarcoma Pelvis > femur > tibia > humerus > fibula osteolytic lesion with cortical destruction, periosteal reaction with the lamellar ‘onionskin’ appearance

32. adamantinoma Involves the tibial diaphysis in up to 90% of cases Expansile , soap bubble lesion with permeation into the medullary canal

33. LIMB SPARING SURGERY (Limb Salvage) Refers to the surgical procedure to restore bone and joint function after extensive resection of malignant bone tumors of the limbs. Maybe performed in more than 85% of Osteosarcomas Consists of 3 phases : a) Resection of tumour b) Skeletal reconstruction (Prosthesis, allograft or arthrodesis) c) Soft tissue and muscle transfers

34. LSS is performed if: 1. Adequate margin for resection of tumor can be obtained with low risk (<10%) of local recurrence. 2. Functional outcome of the reconstructed limb is better than or comparable to that achieved by amputation and prosthetic fitting.

35. Principles of Limb Salvage Major neurovascular bundle must be free of tumour Wide resection should be performed of affected bone with normal cuff in all directions All previous biopsy sites and potentially contaminated tissues should be removed en bloc Bone resected 3 to 4 cm beyond abnormal uptake as in bone scan. The adjacent joint and joint capsule should be resected. Extraarticular resection is preferred and is mandatory in the presence of effusion

36. Tourniquet should be placed proximal to the lesion. Adequate motor reconstruction must be accomplished by regional muscle transfers Adequate soft tissue coverage is needed to decrease the risk of skin flap necrosis and secondary infection Limb salvage can be more aggressively pursued in the upper extremity, where nerve grafting and tendon transfers compensate for loss of major motor nerves

37. Relative Contraindication to Limb Salvage Major neurovascular structures encased by tumor when vascular bypass is not feasible Pathologic fracture with hematoma violating compartment boundary Inappropriately performed biopsy or biopsy- site complications Severe infection in the surgical field Immature skeletal age with predicted leg length discrepancy > 8 cm Extensive muscle or soft-tissue involvement Poor response to preoperative chemotherapy

38. Three-strike rule . Out of the four critical structures namely bone reconstruction, soft tissue reconstruction, nerves, soft tissue envelop (coverage) if any three of the structures are limited (central dark area) simultaneously then limb salvage is possibly not worth considering

39. The various modalities for limb reconstruction used are: Arthrodesis Mobile joint reconstruction – Autoclaved tumor bone – Allograft bone including osteoarticular allograft – Bone transfer (ulna and fibula to reconstruct radius and tibia respectively), Huntington’s procedure – End prosthetic reconstruction –Allograft end prosthetic reconstruction – Custom-made prosthesis – Rotationplasty

40. rotationplasty

41. Techniques in association with Limb salvage A) Modular endoprosthesis allows intraoperative flexibility based on the final amount of tissue resected carries a lower risk of deep infection than do allografts, and nonunion is not a concern avoids the risk of disease transmission and immune responses that are associated with allograft use

42. Early complications : wound necrosis / dehiscence, infection, thromboembolic disease, neuropraxia, and joint instability Late complications : aseptic loosening, infection, joint or prosthetic instability, fatigue, fracture of the prosthesis, and wear or dissociation of modular components

43. B) Osteoarticular or Bulk Allografts Frozen allografts are most often used Ideal for younger patients as they can limit additional revisions of an end prosthesis Complications : wound related infections, allograft fractures, non union

44. Various bone grafts in common use for reconstruction after tumor excision. (A) autologous fibula, cancellous bone chips and synthetic calcium phosphate cubes; (B) Morselized allograft; (C) Autoclaved graft from excised tumor

45. ALLOGRAFT PROSTHETIC COMPOSITE

46. Surgical margins in lss Primarily based on the relationship of the dissection plane to the tumor and its pseudocapsule .

47. classified into four types 1. INTRALESIONAL MARGINS (EXCISION) Plane of dissection within the tumor mass removing only a portion of the lesion. Gross tumor and its pseudocapsule (containing satellites), and skip lesions in the surrounding normal tissues are all left behind. suited for benign bone lesions such as simple bone cyst, ABC and enchondroma .

48. 2. MARGINAL MARGINS have dissection plane through the pseudocapsule aiming to remove the lesion en bloc leaves behind the skip lesions and microscopic satellite lesions. suited for less aggressive lesions such as ABC, and GCT.

49. 3. WIDE MARGINS en bloc excision of the lesion where plane of dissection passes outside the reactive zone of the lesion Removes the tumor with its pseudo capsule and cuff of normal tissue. Desired margin for most primary bone sarcomas Leaves behind the skip foci.

50. 4) RADICAL MARGINS involves removing the entire compartment(s) in which the tumor has extended Does not define the true margins of excision Can be “marginal” or a “wide excision” depending on the location of the tumor within compartment and its proximity to borders. If the tumor extends till the border of compartment, this will just be a “marginal excision”.

51. REFERENCES Campbell’s operative orthopaedics 13 th edition Apley and Solomon’s system of orthopaedics and trauma 10 th edition Differential diagnosis in orthopaedic oncology – 2 nd edition Pubmed central : enneking classification: benign and malignant tumors of the musculoskeletal system. PMC2882012. Pubmed central : Guideline for Limb-Salvage Treatment of Osteosarcoma. PMC7454155 World Health Organization classification of bone tumors (fifth edition): What a radiologist needs to know? Indian Journel of Musculoskelet Radiology 2022;4:73-86

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