This document discusses bone and soft tissue tumors. It provides information on imaging features, benign versus malignant tumors, and primary versus secondary tumors. It discusses factors such as age of the patient, location within the bone, rate of growth, margins, periosteal reaction, matrix, patterns of mineralization, size, number, and soft tissue components that are important for tumor characterization and differential diagnosis. Specific benign bone tumors discussed in detail include fibrous dysplasia, osteochondroma, enchondroma, osteoma, osteoid osteoma, aneurysmal bone cyst, giant cell tumor, osteoblastoma, and non-ossifying fibroma.

1. BONE AND SOFT
TISSUE TUMORS
Nurul Azimah
Dr Nik Farhan

2. BONE TUMORS
­ Imaging features
­ Benign
­ Malignant
­ Primary or secondary tumor (i.e Radiation, Pagets)

3. IMAGING FEATURES
vMorphology
vAge
vLocation
vGrowth pattern/ margin/ zone of transition
vPeriosteal reaction
vMatrix mineralization
vSize and no
vSoft tissue component

5. AGE OF PATIENT
Patient age is of huge importance in suggesting a differential diagnosis of a
focal bone lesion.
Primary bone tumors are rare below age 5yo and over the age of 40yo, with
exception of myeloma and chondrosarcoma.
Metastasis are the commonest lesions over the age of 40yo

6. AGE OF PATIENT
­ Simple bone cyst and chondroblastoma occur in
skeletally immature people
­ Ewing sarcoma typically in 10-20 years old
patients
­ Osteosarcoma has two age peaks; in teenagers
and in pagetic bone or previously irradiated
bone (>50 years old)
­ Malignant bone lesion in adult >40 years old
are metastatic carcinoma, multiple myeloma
and metastatic non-Hodgkin lymphoma rather
than primary bone sarcoma.

7. LOCATION: EPIPHYSIS -
METAPHYSIS - DIAPHYSIS
Epiphysis
Only a few lesions are located in the epiphysis.
In young patients - either a chondroblastoma or an
infection.
In patients over 20, a giant cell tumor has to be
included in the differential diagnosis.
In older patients a geode (degenerative subchondral
bone cyst) must be added to the differential
diagnosis.
Metaphysis
NOF, SBC, Osteosarcoma, Chondrosarcoma,
Enchondroma and infections.
Diaphysis
Ewing's sarcoma, SBC, ABC, Enchondroma, Fibrous
dysplasia and Osteoblastoma.

8. LOCATION WITHIN
THE BONE
Eccentric within bone
giant-cell tumor, chondroblastoma, aneurysmal
bone cyst, non-ossifying broma, and the rare
chondromyxoid broma are located
eccentrically within the bone.
Central (in the middle of a long bone)
Simple bone cyst, enchondroma, and fibrous
dysplasia are located centrally within the bone.

9. RATE OF GROWTH
Most important feature is nature of the
margin
Lodwick classification
Type 1: geographic (benign and low grade
malignant tumor)
­ 1A: thin, rim sclerotic margin
­ 1B: well-defined lesion, but no marginal sclerosis
­ 1C: indistinct border
Type 2: moth-eaten
type 3: permeative (most aggressive)

12. RATE OF GROWTH

13. MARGIN/ ZONE OF TRANSITION
§ In order to classify osteolytic lesions as well-defined or ill-defined, we
need to look at the zone of transition between the lesion and the
adjacent normal bone.
§The zone of transition is the most reliable indicator in determining
whether an osteolytic lesion is benign or malignant.
§The zone of transition only applies to osteolytic lesions since sclerotic
lesions usually have a narrow transition zone.

14. MARGIN/ ZONE OF TRANSITION
Wide transition zone
Ill-defined border + broad TZ = aggressive
growth
Narrow transition zone
Sharp, well-defined, sign of slow growth
NOF SBC ABC

16. PERIOSTEAL REACTION
§Non-specific reaction and will occur
whenever the periosteum is irritated by
a malignant tumor, benign tumor,
infection or trauma.
§2 types:
­ Benign – benign lesion and following
trauma
­ Aggressive – malignant tumors, benign
lesions with aggrasive behavior eg.
Infection or EG
*Malignant lesions never cause benign
periosteal reaction

17. PERIOSTEAL
REACTION
Benign periosteal reaction in osteoid
osteoma

18. PERIOSTEAL
REACTION
Osteosarcoma with Codman's triangle
proximally.
.

19. PERIOSTEAL
REACTION
Ewing sarcoma with lamellated and
focally interrupted periosteal reaction

20. PERIOSTEAL
REACTION
Osteosarcoma with sunburst periosteal
reaction

22. MATRIX
Matrix – type of tissue of the tumor
­ Osteoid, chondral, fibrous, adipose
­ All of these are radiolucent
Mineralization – calcification of the matrix
Certain tumours have characteristic matrix mineralization, which are radiographically visibleand
allows the histological cell type to be predicted.

23. PATTERNS OF MINERALIZATION
Chondral calcification – linear, curvilinear, punctate,
ring-like or nodular
* image: enchondroma with punctate and arc-like
mineralization

24. PATTERN OF MINERALIZATION
Osseous calcification – fluffy,
amorphous, cloud-like, poorly defined

26. SIZE AND NUMBER
•Size can be a clue to diagnosis
•Osteoid osteoma vs osteoblastoma = histologically similar lesion
• nidus of osteoid osteoma <1.5cm , osteoblastoma >1.5cm in diameter
•Primary bone tumors are solitary
•Multiple sclerotic lesions might represent metastasis or osteopoikilocytosis (multiple
bone islands)
•Most common causes of multiple lucencies in >40 years old are metastatic carcinoma,
multiple myeloma and metastatic non-Hodgkin lymphoma
• benign entity like multiple brown tumors may look similar.

27. SOFT TISSUE COMPONENT
Soft tissue component with a bone lesion
suggest malignant process.
May have destroyed the cortex as the tumor
expanded.
Eg:
Osteosarcoma, Ewing sarcoma, lymphoma.

29. BENIGN BONE TUMOR

30. BENIGN LYTIC BONE LESIONS *FEGNOMASHIC*

32. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

33. FIBROUS DYSPLASIA
§ Developmental disorder, 7% of benign bone
tumor
§ Monostotic (70-85%) or polyostotic
§<30 years old (75%)
§ Usually painless, unless fracture
§Common sites for monostotic are the ribs, proximal
femur, and craniofacial bones.
§Has predilection for the pelvis, proximal femur,
ribs, and skull
§Malignant change in fibrous dysplasia is rare
§Association
§McCune–Albright syndrome :
§Polyostotic fibrous dysplasia (typically
unilateral) + ipsilateral cafe ́ au lait spots
(coast of Maine) + endocrine disturbances
(commonly precocious puberty in girls)
§Mazabraud’s syndrome:
§FD (commonly polyostotic) + soft tissue
myxomata

34. FIBROUS DYSPLASIA –
RADIOGRAPHIC FEATURES
§No periosteal reaction
§ Often purely lytic with bone expansion + ground
glass matrix mineralization
§ Endosteal scalloping
§ Rind sign is characteristic – thick sclerotic margin
§ Shepherd's crook deformity – Varus deformity of
proximal femur; characteristic late finding
§ Typical location: metadiaphyseal region
§ Discriminator: No periosteal reaction

35. RIND SIGN

36. SHEPHERD'S CROOK DEFORMITY

37. When fibrous dysplasia affects the ribs,
the posterior ribs often demonstrate a
lytic expansile appearance.
When the anterior ribs are involved, they
are most often sclerotic in appearance.

38. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

39. OSTEOCHONDROMA
§ Benign cartilage-capped bony growth projecting outward from
bone, often pedunculated. It is the most common benign bone
lesion.
§ Present from 2 to 60 years, highest incidence is in the second
decade
§ Arises from the metaphysis and grows away from the epiphysis.
§ Key features are the continuity of cortex of host bone with the
cortex of the osteochondroma and communication of the
medullary cavities.
§Location:
§ Metaphysis of long bones (70%) – femur, tibia, humerus
§ Hands and feet
§ Pelvis
§ Present as a palpable mass, which usually stops growing at
skeletal maturity.
§ Growth after maturity suggest malignancy degeneration (1%)

40. OSTEOCHONDROMA –
RADIOGRAPHIC FEATURES
§ Cartilage-capped bony projection + calcification of hyaline
cartilage cap
§ Pedunculated type – pedicle directed away from joint
§ Sessile type - arise from a broad base
§ Malignant degeneration
§ thick bulky cartilaginous cap (thickness >1cm by CT, >2cm by
MRI)
§ dispersed calcifications within cartilaginous cap
§ soft tissue mass

42. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

43. ENCHONDROMA
• Enchondroma is an intramedullary neoplasm
comprising lobules of benign hyaline
cartilage
• Age range: 0–80 years, with most
presenting in 20-40s
•Location:
• Proximal phalanges (40-50%)
• Metacarpals (15-30%)
• Middle phalanges (20-30%)
• Femur, tibia, humerus (25%)
• Ollier's disease is multiple enchondromas.
• Maffucci's syndrome - multiple enchondromas
with soft tissue hemangiomas.

44. ENCHONDROMA –
RADIOGRAPHIC FEATURES
• Well-circumscribed, lobular or oval lytic lesions
• Expansion of cortex without cortical break
• Chondral-type mineralization may be identified within the
matrix.
• Present centrally in metaphyseal or diaphyseal
• No periosteal reaction or soft tissue mass
•Discriminator:
1. Must have calcification (except in phalanges)
2. No periosteal reaction

45. ENCHONDROMA
Ollier’s and Maffucci’s syndrome

47. ENCHONDROMA VS LOW GRADE CHONDROSARCOMA
§ Distinguishing between enchondromas and low-grade chondrosarcomas is a frequent
difficulty as the lesions are both histologically and radiographically very similar.
§ However, this differentiation may not be of clinical relevance, since both can either be closely
followed up clinically and radiologically or treated if symptomatic.
§ Size: over 5-6 cm favors chondrosarcomas
§ Cortical breach seen in 88% of long bone chondrosarcomas
§ Deep endosteal scalloping involving > 2/3 of cortical thickness seen in 90% of
chondrosarcomas
§ Permeative or moth-eaten bone appearance seen in high-grade chondrosarcomas
§ Chondrosarcomas almost always present with pain
§ Location: Hands and feet are uncommon locations for chondrosarcoma

48. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

49. OSTEOMA
• Slow-growing tumour representing dysplastic
developmental anomaly.
• Cortical > cancellous bones.
•Location:
• Cortical osteomas commonly affect PNS
• May interfere with drainage of PNS
• Frontal and ethmoidal > sphenoidal
• Multiple osteomas in Gardner’s syndrome.
•Histological patterns
•1. ivory osteoma
• dense bone lacking Haversian system
•2. mature osteoma
• resembles 'normal' bone, including
trabecular bone often with marrow
•3. mixed osteoma
• a mixture of ivory and mature histology

50. OSTEOMA
Ivory osteoma Mature osteoma

51. OSTEOMA – RADIOGRAPHIC
FEATURES
• Dense ivory-like sclerotic
mass
• Well-defined margin
• No associated osseous
destruction
• Rarely exceeds 2-3cm in
diameter

52. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

53. OSTEOID OSTEOMA
Benign osteoblastic lesion characterised by a nidus of osteoid
tissue surrounded by reactive bone sclerosis.
Clinical Features:
­ 2nd and 3rd decade, M: F = 2-3:1
­ Night pain relieved by aspirin
Location:
­ >50% in diaphysis or metaphysis of tibia and femur

54. OSTEOID OSTEOMA –
RADIOGRAPHIC FEATURES
• Nidus ; can be lucent, sclerotic
or mixed density
• < 10–15mm in diameter
(mostly < 5 mm)
• Surrounding reactive medullary
sclerosis and solid periosteal
reaction

55. OSTEOID OSTEOMA
AP plain film of the femur in a child with hip pain.
Area of sclerosis medially near the lesser trochanter
with a small lucency (arrow), which is the nidus of
an osteoid osteoma.
CT scan of the femur shows the sclerosis medially and the
lucent nidus (arrow)

56. Osteoid osteoma.
Lateral radiograph of the tibial diaphysis shows
solid thickening of the cortex, within which is a
small calcified nidus (arrow).

57. OSTEOID OSTEOMA VS OSTEMYELITIS
Because an osteoid osteoma resembles osteomyelitis, regardless of the appearance of the nidus, it can
be difficult to differentiate the two radiographically. In fact, it cannot be done with plain films, CT scan,
or MRI scans.
However, because the nidus is extremely vascular, it avidly accumulates radiopharmaceutical bone
scanning agents. An osteoid osteoma will have an area of increased uptake corresponding to the area
of reactive sclerosis, but, in addition, it will demonstrate a second area of increased uptake
corresponding to the nidus (Figures 8-13 to 8-15). This has been termed the double-density sign.
In contrast, osteomyelitis has a photopenic area corresponding to the plain film lucency, which represents
an avascular focus of purulent material.

59. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

60. ANEURYSMAL BONE CYST (ABC)
• Expansile multicystic lesion seen in children and adolescents (<30 years old).
• Consists of blood filled sinusoids and solid fibrous elements.
• May arise secondarily within a pre-existing tumor. (eg. in non-ossifying fibroma,
chondroblastoma, giant cell tumour, fibrous dysplasia, osteoblastoma and
osteosarcoma)
• Location:
• Long bones (> 50%)
• Spine (20%)
• Pelvis (5–10%)
•Diff dx: osteoblastoma, telangiectatic osteosarcoma

61. ABC – RADIOLOGICAL
FEATURES
§ The classical lesion (accounting for 75–80%) is a purely
lytic, expansile intramedullary lesion
§ Metaphysis (most cases), diaphysis (20%)
§ Extending to growth plate.
§ Extends to the growth plate (rarely extension to the
articular surface)
§ May be centrally or eccentrically (more common)
§ Sclerotic margin
§ Trabeculations within the lesion
§Discriminators:
§ Lesion must be expansile
§ Patient must be younger than 30

62. ABC

63. ABC
CT showing a proximal tibial aneurysmal
bone cyst with evidence of faint septal
ossification (arrowheads)

64. ABC
Xray tibia/fibula – eccentric lucent bone lesion at metaphysis tibia.
Axial T2 fatsat MRI images show multiple fluid-fluid levels within the
expansile bone lesion in the proximal tibia.

65. ABC
ABC involving posterior elements of thoracic
vertebral body with fluid-fluid levels.
DDx Expansile Lytic Lesion of
Posterior Element of Spine
• ABC
• Osteoblastoma
• TB

66. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

67. GIANT CELL TUMOR / OSTEOCLASTOMA
• Aggressive benign neoplasm arising from osteoclasts.
• Almost exclusively in adults
• 5% of all primary bone tumors, 20% of benign tumors
• 5-10% of GTC are malignant
• Common sites:
• Distal femur and proximal tibia (55%)
• Distal radius (10%)
• Proximal humerus (6%)
• Sacrum - the most frequent site in spine
• Multifocal, metachronous GCT has also been reported, which is associated with
hyperparathyroidism.

68. GCT – RADIOGRAPHIC
FEATURES
4 classic features in long bone
★ occurs only with a closed epiphyses
★ must be epiphyseal and abuts articular surface: 98-
99%
★ eccentric: if large this may be difficult to assess
★ well-defined with non-sclerotic margin (does not apply
in flat bones eg pelvis and calcaneus)
• Pathological fracture may be present
• No matrix calcification/mineralisation

69. GCT
A large, well-defined lytic lesion in the iliac wing with a
sclerotic margin and does not appear to abut any
articular surface.
The usual rules for giant cell tumors such as the presence
of a nonsclerotic margin do not apply in flat bones.

70. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

71. OSTEOBLASTOMA
• Possesses histological similarities to osteoid osteoma and is differentiated primarily by its size
(>1.5 cm)
• Rare 1-3% of all primary bone tumors
• Occurs mainly in children and adolescents (Over 80% <30 years)
• Presentation : painful scoliosis, dull pain (worse at night, rarely relieved by aspirin), swelling, tender, reduced
ROM.
• Locations:
• Spine (40%) – posterior elements >60%
• Long bones 30% (most common humerus)
• Hands and feet 15%
• Usually monostotic (single bone involvement)
• Metaphyseal or diaphyseal of long bones
• Lesion arises in the medullary cavity, although a periosteal location has also been described.

72. OSTEOBLASTOMA –
RADIOGRAPHIC FEATURES
q Predominantly lytic, measuring over
2cm in diameter
q Larger lesions showing a greater
degree of matrix mineralization (50%)
and bone expansion with or without a
surrounding shell of reactive bone.
q Can cause extracortical mass
Have 2 appearances:
1. Look like large osteoid osteoma
2. Simulate aneurysmal bone
cysts(ABCs). Expansile, often soap
bubble appearance. If ABC is being
considered, so should an osteoblastoma.

74. BENIGN BONE TUMORS
1. Fibrous Dysplasia
2. Osteochondroma
3. Enchondroma
4. Osteoma
5. Osteoid Osteoma
6. Aneurysmal Bone Cyst
7. Giant Cell Tumour / Osteoclastoma
8. Osteoblastoma
9. Non Ossifying Fibroma(NOF)

75. NON OSSIFYING FIBROMA (NOF)
§ Benign well-defined, solitary lesion due to proliferation of fibrous tissue.
It is the most common bone lesion.
§ Patients usually present in the second decade of life
§ The majority (~90%) involve the lower limbs, particularly the tibia and distal end of the
femur.
§ Multiple lesions is associated with neurofibromatosis (5%). The Jaffe–Campanacci syndrome
consists of multiple (usually unilateral) NOFs with café-au-lait spots but no other stigmata of
neurofibromatosis.
§ NOF can usually be diagnosed radiologically, in which case biopsy is unnecessary.
Discriminators:
Must be under age 30.
No periostitis or pain.

76. NON-OSSIFYING FIBROMA
– RADIOGRAPHIC
FEATURES
- Multiloculated lucent lesion with a sclerotic
rim.
- Located eccentrically in the metaphysis,
adjacent to the physis.
- As the patient ages, they seem to migrate
away from the physis.
- No associated periosteal reaction, cortical
breach or associated soft tissue mass.
- Frequently a coincidental finding with or
without a fracture.

77. NOF

80. FURTHER READING WELL DEFINED OSTEOLYTIC
TUMOR & TUMOR LIKE LESION
Eosinophilic granuloma
Solitary bone cyst
Chondroblastoma
Chrondromyxoid fibroma
Infection
Hyperparathyroidism

81. TAKE HOME MESSAGE
FEGNOMASHIC

82. REFERENCES
1. Clyde A Helms, Fundamental Skeletal Radiology
2. Diagnostic Imaging Orthopedics
3. Grainger and Allisos Diagnostic Radiology
4. Radiologyassistant
5. Radiopedia