This document discusses the radiographic approach to evaluating bone tumors. It begins with a review of anatomy and plain X-rays, noting key features to assess. It then discusses common locations of various bone tumors and how location within the bone (epiphysis, metaphysis, diaphysis) and transverse position (centric, eccentric) provide clues. Age at presentation and tumor size, growth rate, periosteal reaction, zone of transition, bone destruction pattern, cortical involvement, and matrix mineralization are all important radiographic factors discussed for differential diagnosis.

1. APPROACH TO
BONE TUMOURS
Dr. Soe Moe Htoo
Radiology PG
DSMA, Myanmar

2. Anatomy Review

3. Plain X rays (SEVEN)
1. Where is the lesion? (What bone & what part of the bone?)
2. Age & size of the lesion?
3. What is the lesion doing to bone?
4. What is the bone doing in response?
5. Is the lesion making matrix?
6. Is the cortex eroded?
7. Is a soft tissue mass evident?

4. LOCATION

5. Top five location of bone tumors
• Aneurysmal Bone Cyst - Tibia, femur, fibula, spine, humerus
• Adamantinoma - Tibia shaft, mandible
• Chondroblastoma - femur, humerus, tibia, tarsal bone (calc), patella
• Chondromyxoid fibroma - Tibia, femur, tarsal bone, phalanx foot, fibula
• Chondrosarcoma - femur, rib, iliac bone, humerus, tibia
• Chordoma - sacrococcygeal, spheno-occipital, cervical, lumbar, thoracic
• Eosinophilic Granuloma - femur, skull, iliac bone, rib, vertebra
• Enchondroma - phalanges of hands and feet, femur, humerus, metacarpals,
rib

6. • Ewing's sarcoma - femur, iliac bone, fibula, rib, tibia
• Fibrous dysplasia - femur, tibia, rib, skull, humerus
• Giant Cell Tumor - femur, tibia, fibula, humerus, distal radius
• Hemangioma - spine, ribs, craniofacial bones, femur, tibia
• Lymphoma - femur, tibia, humerus, iliac bone, vertebra
• Metastases - vertebrae, ribs, pelvis, femur, humerus
• Non Ossifying Fibroma - tibia, femur, fibula, humerus

7. • Osteoid osteoma - femur, tibia, spine, tarsal bone, phalanx
• Osteoblastoma - spine, tarsal bone (calc), femur, tibia, humerus
• Osteochondroma - femur, humerus, tibia, fibula, pelvis
• Osteomyelitis - femur, tibia, humerus, fibula, radius
• Osteosarcoma - femur, tibia, humerus, fibula, iliac bone
• Solitary Bone Cyst - proximal humerus, proximal femur, calcaneal bone,
iliac bone

8. LOCATION (Longitudinal Plane)
1. Epiphysis
2. Metaphysis
3. Diaphysis

9. Epiphysis
• Only a few lesions
• Young patients  Chondroblastoma / Infection
• Over 20 years  GCT has to be included in the differential
• Older patients  Geode must be added to the differential

10. Metaphysis
• NOF, SBC, CMF, Osteosarcoma, Chondrosarcoma, Enchondroma and
Infections
Diaphysis
• Ewing's sarcoma, SBC, ABC, Enchondroma, Fibrous dysplasia and
Osteoblastoma

12. Sites of origin of bone tumours

13. LOCATION (Transverse Plane)
1. Centric
2. Eccentric
3. Cortical
4. Juxta-cortical

14. Centric
• SBC, eosinophilic granuloma, fibrous dysplasia, ABC and
enchondroma
Eccentric
• Osteosarcoma, NOF, chondroblastoma, chondromyxoid fibroma, GCT
and osteoblastoma
Cortical
• Osteoid osteoma
Juxta-cortical
• Osteochondroma. The cortex must extend into the stalk of the lesion.
Parosteal osteosarcoma arises from the periosteum.

15. 1. SBC: central diaphyseal
2. NOF: eccentric metaphyseal
3. SBC: central diaphyseal
4. Osteoid osteoma: cortical
5. Degenerative subchondral cyst:
epiphyseal
6. ABC: centric diaphyseal

16. AGE AT PRESENTATION
• Age is the most important clinical clue in differentiating possible bone
tumors
• Primary malignant bone tumours are rare before 5 years of age
• 1st decade: Commonly disseminated bone lesions of leukaemia and
neuroblastoma
• 2nd decade: Commonly an osteosarcoma or Ewing’s sarcoma
• > 45 years of age: Metastases are the commonest

17. Specific tumors by age
Malignant bone tumors(red) and benign tumors(blue)

19. SIZE
• The likelihood of malignancy increases with the size of bony lesions.
• For example, a 1-2 cm chondral lesion in a long bone is most likely to
be an enchondroma, while the risk of being a low-grade
chondrosarcoma increases if it is greater than 4 or 5 cm.
• The size of a lesion can also be a clue to its diagnosis. For example,
the nidus of the osteoid osteoma is less than 1.5 cm in diameter, while
the osteoblastoma is larger than 1.5 cm.
• In general, large lesions more likely to be aggressive or malignant.
(Except: Fibrous Dysplasia)

20. RATE OF GROWTH
Benign and low-grade malignant neoplasms
• remain within the intramedullary cavity (until late)
• slow erosion of the endosteal cortex (leading to endosteal scalloping)
• periosteal new bone formation can lead to bone expansion and a well-
defined sclerotic rim
High-grade malignant tumours
• extend through the cortex at presentation with associated cortical
destruction,
• non-sclerotic rim and an adjacent extraosseous mass

21. PERIOSTEAL REACTION
• Due to periosteum irritation by a malignant tumor, benign tumor,
infection or trauma.
• Non-specific, non-pathognomonic
• Indicate the aggressiveness of a lesion
• Two patterns:
1. Benign type - in benign tumors and following trauma
2. Aggressive type - in malignant tumors, in benign lesions with
aggressive behavior(Infections & Eosinophilic granuloma)

22. Periosteal reaction

25. Benign periosteal reaction
• Thick, wavy and uniform callus formation resulting from chronic
irritation
• Thick bone and remodeling, more normal appearing cortex
• In benign and slow growing lesions
• Malignant lesions never cause a benign periosteal reaction

26. Thick well-formed (solid) periosteal reaction
• Indicates slow rate of growth
• Benign tumour, low-grade chondrosarcoma
A solid periosteal reaction
due to osteoid osteoma

28. Benign periosteal reaction in an osteoid osteoma

29. Aggressive periosteal reaction
• Multilayered, lamellated or demonstrates bone formation perpendicular to
the cortical bone
• Periosteum does not have time to consolidate
• May be spiculated and interrupted ± Codman's triangle

30. Laminated (‘onion peel’) periosteal reaction
• Indicates subperiosteal extension of
tumour, infection or haematoma
• Demonstrate periodic growth
• May show a multi-laminated pattern
(e.g. Ewing’s sarcoma)
(1) A single-laminated periosteal reaction
associated with a Brodie’s abscess
(2) A multi-laminated periosteal reaction
associated with Ewing’s sarcoma

31. Spiculated, vertical or ‘hair-on-end’ periosteal reaction
• Seen in the most aggressive tumours
• E.g. Osteosarcoma or Ewing’s sarcoma
• Most rapidly growing lesions may not be
associated with any radiographically
visible periosteal reaction (as minerali-
zation of periosteum can take weeks)
A ‘hair-on-end’ type vertical periosteal reaction
associated with Ewing’s sarcoma.
Note also the Codman’s triangle (arrow).

32. Codman's triangle
• Elevation of the periosteum away from the cortex, forming an angle
where the elevated periosteum and bone come together
• Indicates the limit of subperiosteal tumour in a longitudinal direction
bone formation
• Only occurs at the tumour margins

34. 1. Osteosarcoma 2. Ewing sarcoma 3. Infection

35. Ewing sarcoma of femur (AP & Lateral)
Mottled, osteolytic lesion (blue circle) with poorly marginated edges in
the diaphysis of the bone
Sunburst periosteal reaction (red circle) and
Lamellated periosteal reaction (white arrows)

38. ZONE OF TRANSITION
• To classify well-defined or ill-defined, look zone of transition
(between the lesion and the adjacent normal bone)
• It is the most reliable indicator in determining benign or malignant.
• It only applies in osteolytic lesions

39. Small zone of transition
• Sharp, well-defined border
(sign of slow growth)
• Sclerotic border
(indicates poor biological activity)
•

40. Wide zone of transition
• Feature of malignant bone tumors
• Ill-defined border with a broad zone of transition (sign of aggressive
growth)
• Two tumor-like lesions (Infections & Eosinophilic granuloma) may
mimic malignancy d/t their aggressive biologic behavior.

41. Wide zone of transition indicates:
Malignancy or Infection or Eosinophilic granuloma

42. Patterns of Bone Destruction
(Lodwick Classification)
• For describing the margins of a lucent/lytic bone lesion
• Used in the description for aggressive and possibly malignant
Classification
• Type 1: Geographic
• Type 2: Moth-eaten
• Type 3: Permeative

43. A: Pattern of medullary destruction
B: Margination of lesions

45. Lodwick pattern I (geographical)
Types
1A: Well-defined lucency with sclerotic
rim (Intra osseous lipoma)
1B: distinct, well- marginated border,
without sclerotic rim (Myeloma)
1C: indistinct border, ill-defined lytic
lesion (Osteosarcoma)
• Benign and low-grade malignant neoplasms
• Narrow zone of transition (a few mm)
• Most actively growing lesions (e.g. a GCT) have a non-sclerotic margin
• Least aggressive lesions show a sclerotic rim of varying thickness

50. Radiograph showing a lymphoma in the humerus with the
moth-eaten appearance typical of round cell tumors

54. Most common sclerotic bone tumours

55. Benign Lesions without Sclerotic Borders
• Giant cell tumour
• Brown tumour
• Osteolytic Paget’s

56. Lodwick pattern II (moth-eaten)
• The next most aggressive pattern
• Probably malignancy
• The zone of destruction is made up of multiple
ill-defined coalescing lucent areas (2–5mm)
and implies cortical involvement (purely
medullary lesions are not visible)

57. Lodwick pattern III (permeative)
• Most malignant pattern
• Composed of multiple coalescing
small ill-defined lesions (≦ 1mm)
with a zone of transition of several
cm
• XR can underestimate the extent of
involvement
A primary bone lymphoma showing a
‘permeative’ pattern of bone destruction

58. ‘Saucerization’ of the outer cortical margin
• Tumour is temporarily restrained by the periosteum, erodes back
through cortical bone
• Is the excavation of the outer cortical margin of long tubular bones
that can be seen with soft-tissue masses
Examples:
• Malignant round cell tumours
• Steosarcoma
• Most metastases
• Certain stages of osteomyelitis
• Langerhans cell histiocytosis

59. CORTICAL DESTRUCTION
• Common finding
• Destruction of cortex by a lytic or sclerotic process
• Not very useful in distinguishing between benign and malignant
• Complete destruction seen in high-grade malignant lesions and in
locally aggressive benign lesions like EG and osteomyelitis.
• Uniform cortical bone destruction in benign and low-grade malignant
lesions.

60. Patterns of cortical disturbance

61. Cortical bone reaction. A, Expansile. B, Endosteal scalloping.
C, Thin, nearly imperceptible. D, Destructive. E, Saucerization.

62. Endosteal scalloping
• Thinning of the cortex by an
intraosseous process
• Focal resorption of the inner layer of the
cortex (i.e. the endosteum) of bones
• Due to slow-growing medullary lesions.
• Evidence of slow non-infiltrative lesion
• But, not indicate benignity

64. DDx of Endosteal Scalloping
Benign
• enchondroma
• chondromyxoid fibroma
• chondroblastoma
• brown tumour
• skeletal amyloidosis
• osteomyelitis
• fibrous dysplasia
• anaemias
• periprosthetic osteolysis
Malignant
• chondrosarcoma (low grade)
• skeletal metastases
• multiple myeloma
Multiple myeloma - femur

65. 1. Irregular cortical destruction in an osteosarcoma
2. Cortical destruction with aggressive periosteal reaction
in Ewing's sarcoma.

66. Ballooning
• Special type of cortical destruction
• Destruction of endosteal cortical bone and the addition of new bone on
the outside occur at the same rate, resulting in expansion.
• This 'neocortex' can be smooth and uninterrupted, but may also be
focally interrupted in more aggressive lesions like GCT.

67. Chondromyxoid fibroma
- Benign, well-defined, expansile lesion
with regular destruction of cortical bone
and a peripheral layer of new bone.
Giant Cell Tumour
- Locally aggressive lesion with cortical
destruction, expansion and a thin, interrupted
peripheral layer of new bone
- Wide zone of transition towards the marrow
cavity

68. Malignant small round cell tumors
(Ewing's sarcoma, bone lymphoma and small cell osteosarcoma)
• Cortex may appear almost normal radiographically
• Tumors may be accompanied by a large soft tissue mass without cortical
destruction (from permeative growth throughout the Haversian channels)

69. • Ewing's sarcoma with permeative
growth through the Haversian
channels accompanied by a large
soft tissue mass.
• The radiograph does not shown
any signs of cortical destruction

70. MATRIX MINERALIZATION
• Calcifications or mineralization within a bone
lesion may be an important clue in the
differential diagnosis
• Two kinds of mineralization:
- Chondroid matrix in cartilaginous tumors
- Osteoid matrix in osseous tumors

72. Tumor bone formation, matrix calcification

73. Osseous mineralization
• Cloud-like and poorly defined, diffuse matrix
mineralization
• Trabecular ossification pattern in benign bone
forming lesions
• Cloud-like or ill-defined amorphous pattern in
osteosarcomas
• Sclerosis can also be reactive, e.g. in Ewing’s
sarcoma or lymphoma.
Osteosarcoma showing
typical osseous mineralization

74. Osteoid matrix
Cloud-like bone formation in osteosarcoma.
Notice the aggressive, interrupted periosteal
reaction (arrows).
Trabecular ossification pattern in
osteoid osteoma.
Notice osteolytic nidus (arrow).

75. Chondroid mineralization
• Linear, curvilinear, ring-like, punctuate or nodular
• Often central
• Peripheral in benign lesions such as a bone infarct or
myositis ossificans
• Calcifications in chondroid tumors have many
descriptions: rings-and-arcs, popcorn, focal stippled
or flocculent.
Metachondromatosis showing
typical chondroid calcification.

77. Chondroid matrix
• Enchondroma, the most commonly encountered lesion of the phalanges.
• Peripheral chondrosarcoma, arising from an osteochondroma (exostosis).
• Chondrosarcoma of the rib.

78. Diffuse matrix
• Shows ground-glass density
• Punctate calcification may also be present
• Seen in benign fibrous tumours
Fibrous dysplasia showing typical
ground-glass mineralization

80. Osteolytic lesion
• Punched-out area of severe bone loss
Lytic Lesions in Children
• Eosinophilic granuloma
• Neuroblastoma
• Leukemia
Lytic Lesions in Adults
• Metastatic lesions (Lung, Renal, Thyroid)
• Multiple myeloma
• Primary bone tumor

81. Osteoblastic
• Relating to the osteoblasts
• Any region of increased radiographic bone density
Blastic Lesions in Children
• Medulloblastoma
• Lymphoma
Blastic Lesions in Adult
• Metastatic disease (Breast –female, Prostate –male)
• Lymphoma
• Paget’s disease

82. Soft Tissue Extension
• Usually implies malignancy
• More likely to form discrete soft tissue mass
Benign conditions with soft tissue extension
• mass is not well-defined and fat planes are affected.
• Osteomyelitis usually infiltration of fat

85. Polyostotic or multiple lesions
• NOF
• Fibrous dysplasia
• Multifocal osteomyelitis
• Enchondromas
• Osteochondoma
• Leukemia
• Metastatic Ewing' s sarcoma
• Multiple enchondromas are seen in Morbus Ollier
• Multiple enchondromas and hemangiomas are seen in Maffucci's
syndrome

86. Polyostotic lesions > 30 years
• Common: Metastases, multiple myeloma, multiple enchondromas.
• Less common: Fibrous dysplasia, Brown tumors of hyperparathyroidism,
bone infarcts.

87. Mnemonic for multiple osteolytic lesions: FEEMHI
• Fibrous dysplasia
• Enchondromas
• EG
• Mets and myeloma
• Hyperparathyroidism
• Infection

88. Chonndrosarcoma

89. Polyostotic Fibrous Dysplasia
Multiple osteolytic lesions in femur

90. Spine Lesions
1. Hemangioma 2. Metastasis 3.Multiple myeloma 4. Plasmocytoma
• Osteoblastoma
• Chordoma
• ABC
• Metastatic disease

95. TAKE HOME MESSAGE
• In patients less than 30 years of age, a narrow zone of transition
indicates benignancy.
• Metastases and Myeloma always have to be included in the differential
diagnosis of a well-defined bone lesion in a patient >40 years
• Infection and Eosinophilic Granuloma can mimic a malignant tumour.
• They can have an ill-defined border, cortical destruction and
aggressive type of periostitis.
• Malignant bone tumours do not cause a benign periosteal reaction.
• A periosteal reaction excludes the diagnosis of fibrous dysplasia,
Enchondroma, NOF and SBC unless there is a fracture.

96. • Infections, a common tumor mimic, are seen in any age group.
• Infection may be well-defined or ill-defined osteolytic, and even
sclerotic.
• EG and infections should be mentioned in the differential diagnosis of
almost any bone lesion
• Many sclerotic lesions in patients > 20 years are healed, previously
osteolytic lesions which have ossified, such as: NOF, EG, SBC, ABC
and chondroblastoma
• In patients > 40 years metastases and multiple myeloma are by far the
most common well-defined osteolytic bone tumors.

97. • In patients > 40 years metastases and multiple myeloma are the most
common bone tumors.
• Metastases and myeloma are also usually well-defined, but sometimes
ill-defined
• In patients > 30 years (particularly >40), despite benign radiographic
features, metastasis or plasmacytoma should to be considered.
• Metastases under the age of 40 are extremely rare, unless a patient is
known to have a primary malignancy.
• Metastases could be included in the differential diagnosis if a younger
patient is known to have a malignancy, such as neuroblastoma,
rhabdomyosarcoma or retinoblastoma.

98. • Patients with Brown tumor in hyperparathyroidism should have other
signs of HPT or be on dialysis.
• Differentiation between a benign enchondroma and a low grade
chondrosarcoma can be impossible based on imaging findings only.
• Ill-defined borders in GCT is seen in a locally aggressive lesion.
• Chondrosarcoma is usually well-defined, but high grade
chondrosarcoma can be ill-defined.

100. THANK YOU