radiographic analysis of bone tumors

oncology

1. Plain Radiographic Analysis of Bone Tumors

2. Plain radiographs are the most important investigation for bone tumors The Presenting Complaints Soft tissue mass - myositis ossificans Painless bony mass Incidental finding Painful bone lesion Pathologic fracture

3. Seven Questions to Ask Where is the lesion? What bone, and in which part of the bone ? How large is the lesion? How extensive are the abnormalities seen on Radiographs? What is the lesion doing to the bone ? What is the bone doing in response ? Is the lesion making matrix? What kind of matrix is being made ? Is the cortex eroded ? Is a soft tissue mass evident?

4. Answers + clinical assessment Biological activity of the lesion can be classified as Benign Latent, Active , Aggressive Malignant Mesenchymal , Myeloproliferative , Metastatic

5. 1.Where is the lesion ? Most important question to ask when developing a differential diagnostic list The particular bone involved as well as the portion of the bone affected must be determined

6. The Affected Bone

7. Symptomatic metastatic tumors are usually found proximal to the knees and elbows The metastatic lesion found distal to knees and elbows are usually from lung cancer, renal cell cancer and melanoma The phalanges are a common site for enchondromas Aggressive and malignant primary bone tumors sites include the metaphyses of the distal femur, proximal tibia, proximal femur, proximal humerus Chondrosarcoma is more frequently found in the proximal skeleton (pelvis, scapula, proximal humerus and femur) Chordoma is most commonly found in the sacrum and at the base of skull

8. The Affected Portion of the Bone

9. Epiphyseal These lesions in adults may extend across the growth plate This is typical of a chondroblastoma Epiphyseal - metaphyseal This is a classic location for locally aggressive tumors such as giant cell tumor of bone Metaphyseal or metaphyseal-diaphyseal Lesions that do not cross the growth plate and tend to grow away enchondroma , unicameral bone cyst Bone abscesses ( Brodie's abscess) The metaphysis is the most common site for primary mesenchymal malignancies ( osteosarcoma , chondrosarcoma )

10. Diaphyseal This is a relatively uncommon location for bone tumors Infections and fractures may cause tumor -like changes Ewing's sarcoma, eosinophilic granuloma , osteoid osteoma , and metastases Peri-articular Changes are present on both sides of the joint Infectious, Inflamatory , Metabolic (Gout) joint vascular tumor , such as disappearing bone disease ( Gorham's disease - angioma or lymphangioma of bone) or angiosarcoma of bone

11. Central Enchondroma Fibrous Dysplasia Eccentric Non-ossifying Fibroma Chondromyxoid Fibroma Juxtacortical Osteochondroma Parosteal Osteosarcoma Cortical Osteoid Osteoma Periosteal Chondroma

12. 2.How large is the lesion ? In general, the larger the lesion, the more likely it is to be aggressive or malignant Conversely, smaller lesions, such as an osteoid osteoma , are usually benign. This is not universally true

13. How extensive are the abnormalities seen on Radiographs? The assessment begins with local radiographs Xrays of other sites or a bone scan may be needed In metastatic bone disease and multiple myeloma, other lesions may be seen in the same Xray endocrine conditions, congenital diseases ( familial osteochondromatosis ), or developmental skeletal dysplasia ( Ollier's disease, Maffucci's disease ) may become obvious when the skeleton surrounding the primary lesion is examined

14. 3.What is the lesion doing to the bone ? Bone tumors have a limited number of potential effects on the skeleton The most common is to produce bone lysis The pattern of lysis and the extent of the host response to lysis provide major clues as to whether the lesion is latent, active, aggressive, or malignant Margin or interface is present between the host bone and the lesion

15. Margin The margin of the lesion and the zone of transition between lesion and adjacent bone are key factors in determining if a lesion is aggressive or nonaggressive . A lesion with sharp margins and a narrow transition zone – nonaggressive Illdefined margin and wide zone transition – aggressive

16. Pattern of Bone Destruction • Geographic - Focal discrete lesion +/- sclerosis ( Lodwick pattern I ) • Moth-eaten ( Lodwick pattern II ) • Permeative ( Lodwick pattern III )

17. Type 1a : geographic lesion - well-defined lucency with sclerotic rim Eg . Non ossifying Fibroma

18. Type 1b : geographic lesion-well-defined lucent lesion without sclerotic rim Eg . Aneurysmal bone cyst

19. Type 2 : moth-eaten lesion- patchy lysis of medullary cavity Eg . metastasis

20. Type 3 : permeated lytic lesion - small patchy lucencies in medullary cavity Eg . Ewing’s Sarcoma

21. Geographic Moth-eaten Permeative Non agressive Agressive Pattern Of Destruction

22. 4.What is the bone doing in response? Often, the bone responds by making new bone, which can be seen in either the medullary bone or in the cortex and periosteum The pattern of bone response, especially combined with the pattern of lytic destruction, is very useful in determining whether the lesions is latent, active, aggressive or malignant

23. Periosteal Reaction Periosteum is an envelope of highly vascular tissue consisting of an outer fibrous layer and an inner cellular (cambium) layer that possesses osteoblastic potential It may be elevated from its location adjacent to the underlying cortex by dilated periosteal vessels or edema from passive hyperemia or it may be elevated directly by tumour , pus, or haemorrhage

24. The presence and appearance of periosteal reaction are features that help characterize a bone lesion Solid & unilamellated - slow growing , nonaggressive lesion eg . Osteoid osteoma . Multilamellated or onion skin appearance - intermediate aggressive process eg . Ewing’s sarcoma or acute osteomyelitis Interruption of uni or multilamellated periosteal reaction – aggressive process eg . osteosarcoma

25. Types of Periosteal Reaction Lamellated (single layer) Unilamellated periosteal reaction Diagram shows single layer of reactive periosteum (arrow ) Lamellated (multiple layers) Multilamellated periosteal reaction Diagram shows multilamellated , or onionskin, periosteal reaction (arrow )

26. Solid periosteal reaction Spiculated periosteal reaction / Perpendicular (hair on end) Perpendicular periosteal reaction Diagram shows spiculated , or hair-on-end, periosteal reaction (arrow ) Sunburst Diagram shows radial, or sunburst, periosteal reaction (arrow )

27. Codman’s triangle : Diagram shows elevated periosteum forming an angle with the cortex

28. Solid Lamellated Codman’s Sunburst Non agressive Agressive Periosteal Reaction

29. 5.What kind of matrix is being made ? This question is fundamental to the diagnosis of primary mesenchymal tumors , especially benign and malignant bone and cartilage forming tumors It may be difficult to differentiate calcified cartilage from ossification in tumor matrix Calcium deposition in cartilage is typically less well organized than bone

30. Matrix and minerlisation Matrix : refers to the type of tissue of the tumor - such as osteoid , chondral , fibrous, or adipose, all of which are radiolucent Mineralization : refers to calcification of the matrix Tumors may be lytic , sclerotic, or mixed For example, simple bone cysts and giant cell tumors are lytic , bone islands are sclerotic, and adamantinomas are often mixed

31. Pattern of mineralization can be a clue to the type of underlying matrix and, thus, the diagnosis Chondral tissue often produces punctate , flocculent, comma shaped, or arclike or ringlike mineralization enchondroma,chondrosarcoma , or chondroblastoma Bone-forming tumors have fluffy, amorphous, cloudlike mineralization, causing an opaque radiographic appearance osteosarcoma

32. Chondral mineralization Diagram shows patterns and of mineralization of cartilaginous tumor matrix: stippled (left), flocculent (middle), and ring and arc (right )

33. Diagram shows patterns of mineralization of osseous matrix with solid (left), cloudlike (middle), and ivory-like (right) opacity

34. 6.Is the cortex eroded ? Cortical erosion is the hallmark of the active, aggressive or malignant tumor The pattern of cortical erosion may be highly correlated with the histology of the lesion In chondrosarcoma , (unicameral bone cyst, non-ossifying fibroma ) may cause cortical erosion with minimal periosteal response The erosion of the endosteum caused by chondrosarcoma is often accompanied by well ordered periosteal bone formation on the bone's surface, leading to a pattern of endosteal expansion

35. In an aneurysmal bone cyst or giant cell tumor , the cortex may be completely destroyed, but a thin layer of periosteal neo- corticalization may surround the lesion High-grade malignant tumors , be they primary or metastatic, may erode through the cortex with only an ineffective periosteal response to the erosion

36. 7.Is a soft tissue mass evident MRI and CT scan are generally better The presence of a soft-tissue component with a bone lesion suggests aggressive process The soft-tissue component with obscuration of adjacent fat planes – benign ( acute osteomyelitis ) Soft tissue component with displacement of fat planes - malignant

37. Aggressive tumors almost always develop a soft tissue component by destroying the cortex and expanding into the surrounding tissues Alternately they may grow directly through the haversian system of the cortex leaving cortex structurally intact

38. The hallmark of a soft tissue mass associated with bone sarcoma is that it lies on top of the intact cortex, with sarcoma present inside and outside the cortex. The presence of "malignant" matrix in the soft tissue mass is almost always a sign of a mesenchymal malignancy. Tumors that often have a soft-tissue component are osteosarcoma , chondrosarcoma,Ewing’s sarcoma, and lymphoma

39. Biological Potential of Bone Lesions Benign latent bone lesions Benign active bone lesions Benign aggressive bone lesions Malignant bone lesions

40. Benign latent bone lesions Benign latent lesions have generally been active at some time in the past , but they show evidence of healing at the time of evaluation Examples include adult osteochondromas and non-ossifying fibromas

41. Benign active bone lesions Benign active lesions may have been present in the bone for substantial periods of time and exist in a type of symbiosis with the skeleton The best example is fibrous dysplasia , which may be present for a lifetime and cause minimal symptoms. However and it is possible for the bone to fracture in response to minimal trauma This description applies to active unicameral bone cysts and non-ossifying fibromas that may cause pain and present a risk for fracture in children Another example is an osteoid osteoma . Such lesions are usually active and symptomatic, causing pain but limited destruction of the host bone

42. Benign aggressive bone lesions Benign aggressive lesions cause more substantial bone destruction than active lesions and may also result in pathological fractures. This group of tumors includes giant cell tumor , aneurysmal bone cyst, osteoblastoma , chondroblastoma , and chondromyxoid fibroma . Small soft tissue masses may result from the lesion growing through the cortex, but the periphery of the lesion is often defined by a periosteal neo-cortical response. There is typically no risk of metastasis in these lesions, although a small percentage of giant cell tumors may spread to the lungs.

43. Malignant bone lesions Malignant lesions may be characterized by a number of radiographic changes, including multiple lesions (metastatic lesions seen on bone scan), permeative bone destruction with poorly defined margins , cortical erosion , malignant matrix formation, and the development of a soft tissue mass In differentiating mesenchymal from metastatic bone malignancies, it is useful to determine if the tumor is solitary or multiple Matrix formation and an associated soft tissue mass are more frequent with mesenchymal lesions

44. Radiologic characteristics of benign and malignant bone tumors Benign Well defined Sclerotic border Less aggressive periosteal reaction Absence of soft tissue mass Slow growth Metastasis rare Malignant Destructive poorly defined, permeative Infiltrative border More aggressive periosteal reaction Soft tissue mass or extension Rapid growth Metastasis common

45. Benign Bone Tumors Osteoid Osteoma Enchondroma Fibrous Dysplasia Haemangioma Aneurysmal Bone Cyst Giant Cell Tumor

46. Malignant Bone Tumors Osteosarcoma Ewing’s sarcoma Chondrosarcoma Lymphoma Multiple Myeloma Metastasis

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