The document describes a case of a 32-year-old male who presented with pain and swelling in his right ankle for 1 year and 6 months respectively. On examination, tenderness was found around the swelling. X-ray showed a mixed lytic and sclerotic lesion in the talus with periosteal reaction and soft tissue swelling. Differential diagnoses of Ewing sarcoma, synovial osteosarcoma, and osteomyelitis were provided. The document then discusses the features of osteosarcoma, osteomyelitis, Ewing sarcoma, and synovial sarcoma.

1. Dr. Sheikh Zahidul Islam
Phase-A Resident (R-14)
Radiology And Imaging
BSMMU

2.  Mr. Moktar Hossain, 32 years old male, hailing from
shariatpur presented with the complains of pain in
right ankle for 1year and swelling around ankle for
6months.
 According to statement of the patient, he was
reasonably well 1 year back. Then he developed pain in
his right ankle which was intermittent, non radiating,
aggravated by activity and initially slightly relieved by
painkillers but later became progressive and did not
respond to medication.

3.  For the last 6 months pain is associated with
swelling around ankle which is gradually
increasing in size but there is no discharge from
the swelling. For last 2days the pain bacame more
severe.
 He has no history of trauma, tuberculosis or
diabetes mellitus.
 On examination : There is tenderness around
swelling.

4. Plain X-ray of right
ankle(AP and lateral
view) shows:
-Mixed lytic and
sclerotic lesion
(predominantly sclerotic
lesion) in talus having
wide zone of transition.
-Spiculated periosteal
reaction.
-Massive soft tissue
swelling.
-Reduced bone density.
-POP cast is seen.

5.  Differential diagnosis:
Ewing sarcoma
Synovial osteosarcoma
Osteomyelitis

6.  Osteosarcoma is a mesenchymal malignancy
(malignant spindle cells) that differentiates to produce
osteoid(immature bone).
 It is second most common primary malignant bone
tumor(After multiple myeloma) accounting for about
20% of all primary bone tumor.
 In children, is considered most common primary bone
tumor.
 It has a bimodal age distribution. First peak is in 10-14
years & the second peak is in adults older than 65
years.

7. Osteosarcoma
Primary
Osteosarcoma
Secondary
Osteosarcoma

8.  Central / Intramedullary osteosarcoma:
Conventional osteosarcoma
Telangiectatic osteosarcoma
Small cell osteosarcoma
Low grade osteosarcoma
 Surface / Juxtacortical osteosarcoma:
Parosteal osteosarcoma
Peiosteal osteosarcoma
High grade osteosarcoma
 Intracortical osteosarcoma

9.  It occurs in patients having-
Paget's disease of bone
Fibrous dysplasia
Irradiated bone
Bone infarct
Osteochondroma
Osteoblastoma

10.  Primary osteosarcoma occurs in bone
which has no underlying preexisting
pathology.
 It typically occurs in young patients with
75% taking place before the age of 20
because the growth centers of bones are
more active during puberty and
adolescence.

11.  Commonest type of primary osteosarcoma (75% of all osteosarcoma).
 Most common sites are :
Distal femur(40%)
Proximal tibia(20%)
Proximal humerus(10-15%)
 Other less common sites are :
Proximal femur
Fibula
Vertebrae , pelvis
Maxilla , mandible
Skull etc.
 Sites within the bone: Metaphysis(90%)
Diaphysis(10%)

12. Imaging features of conventional intramedullary osteosarcoma:
 Moth eaten or permeative pattern bone destruction.
 Three types of bone lesions are found:
-Sclerotic/Blastic (50%)
- Lytic(25%)
-Mixed(25%)
 Aggressive periosteal reaction:
-Sunburst/Spiculated/Hair on end appearance
- Codman triangle
-Lamellated / Onion skin appearance(Less Common)
 Large soft tissue shadow is usually present.
 Pathological fracture may be present.

13.  Skeletal metastasis(Skip metastasis)
within the same bone may occur(5-8%
cases).
 Lung metastasis occurs through
haematogenous route (Spontenuous
pneumothorax is a common
presentation of lung metastasis in
osteosarcoma)

14. Plain X-ray Right femur
showing:
 Mixed lytic and
sclerotic lesion in
femoral metaphysis.
 Soft tissue mass with
calcification(arrow
marked area)
 Codman’s
triangle(arrow
marked area)

15.  Plain x-ray of left
ankle AP view
showing sclerotic
lesion in lower part
fibula and tibia with
sunburst type
periosteal reaction
associated with
significant soft tissue
swelling.

16. Plain x-ray right leg AP
view showing :
- Lytic lesion in distal
part of fibula.
-Cortical destruction.
- Soft tissue swelling.

17.  Plain X-ray of left
femur shows skip
metastasis.(arrow
marked area)
 It is an important
feature of conventional
intramedullary
osteosarcoma , that’s
why complete
radiograph of affected
bone should be done to
detect skip skeletal
metastasis.

18.  Plain X-ray
chest of a
patient of
osteosarcoma
showing
multiple
metastatic lung
nodule.

19. Other investigations:
MRI: It must include the entire affected bone to detect
skip metastasis.
CT scan : CT scan of chest may be required to evaluate
pulmonary metastasis.
Bone scan: It is useful to evaluate the extent of local
disease and presence of bone metastasis.
Lab investigation : Raised Serum alkaline
phosphatase(ALP) and Lactate dehydrogenase(LDH)
suggest aggressive disease & poor prognosis.

20. Invasive tests:
 Biopsy and histopathology: To confirm or
rule out diagnosis.
 Immunohistochemistry: It helps in detecting
types and subtypes of tumor by identifying
specific biomarker.
 Treatment: Neoadjuvant chemotherapy,
then limb salvage resection ,followed by
adjuvant chemotherapy.

21.  It is an osteolytic destructive sarcoma.
 Tumor composed of cystic cavities
containg necrosis and hemorrhage.
 About 3% of all osteosarcoma.
 Radiological feature:
X-ray: Osteolytic expansile lesion with
cortical destruction.
CT/ MRI: Fluid-fluid level, enhancing
septa & soft tissue mass are found.

22.  Plain x-ray of right
shoulder AP view
showing expansile
lytic lesion with
cortical destruction
and wide zone of
transition extending
from metaphyseal
region to epiphyseal
region of right
humerus. The lesion is
associated with soft
tissue mass.

23.  About 1-2% of all osteosarcoma.
 Radiographic feature:
-Intracompartmental lytic lesion .
-Ground glass appearance.
-Internal trabeculation.
-Usually no soft tissue extension and
periosteal reaction.

25.  Parosteal osteosarcoma is a juxtacortical
osteosarcoma that arises from outer
periosteum.
 It is relatively slow growing and has a
better prognosis.
 Radiologically is presents with a
juxtacortical mass and string sign(A
radiolucent line between tumor and bony
cortex)

26. Plain x-ray of right knee
AP view showing a
cauliflower like
exophytic mass with
dense calcification in
metaphyseal region of
right femur. Supiriorly a
thin line separates the
mass from tumor(string
sign).

27.  It is a rare type of intermediate grade
osteosarcoma that arises from inner
periosteum.
 It usually affects diaphysis of long bones.
 Radioghraphic feature :
• Broad based cortically attached lesion with rare
intramedullary extension.
• Sunburst periosteal reaction which is often
associated with a saucerised cortical
depression.
• Occasionally codman triangle.

28. X-ray right femur
lateral shows:
 Broad based
eccentric lytic lesion
in diaphyseal
region.
 Saucerised cortical
depression.
 Codman triangle.
 Soft tissue swelling.

29.  X-ray femur
shows sunburst
periosteal
reaction.

32.  Chronic osteomyelitis is a form of osteomyelitis
and is defined as a progressive inflammatory
process resulting in bone destruction and
sequestrum formation.
 The clinical pattern may evolve over months or
even years and is characterised by low grade
inflammation, the presence of pus, sequestra,
involucrum and sometimes a sinus tract/ fistula.
 Draining sinus is a pathognomonic sign.
 Fever and chills are less common.

33.  M:F=4:1
 Risk factor:
-Recent trauma, surgery.
-Systemic condition such as diabetes, sickle
cell disease, IV drug users.
-Poor vascular supply.
-Peripheral neuropathy.
-Immunocompromised individuals.
 Common sites:
-Tarsal ,metatarsal bones and toes.
-Femur, tibia, fibula.
-Spine, sternum, pelvis.
-Upper limbs, jaw.

34.  The following tests support the diagnosis of
osteomyelitis:
CBC:WBC count will be increased.
ESR : It will be increased.
CRP: It correlates with clinical response to
therapy.
Blood culture: It is positive in 50% cases.
It should be obtained prior
to antibiotics , if possible.

35.  Bony lucency
 Sclerotic rim and cortical thickening.
 Reduced bone density.
 Cloaca may be present.
 Soft tissue swelling may be present.
 Periosteal reaction may be found.

36. Plain x-ray of right
femur shows: A
sclerotic bony fragment
surrounded by lucent
rim (sequestrum) in
distal femoral
diaphysis and marked
thickening of adjacent
cortex(Involucrum)

38. Treatment:
 Antiobiotics.
 Sequestrectomy & saucerisation.
 Amputaion is performed after failure of
previous therapy or when the infection is
life threatening.

39.  Ewing’s sarcoma is a malignant , distinctive small
round cell sarcoma of neuroectodermal origin
usually associated with a t(11:22) translocation.
Occurs most commonly in second decade(80%
occurs between 5-25 years with a peak at 15 years)
 It has high metastatic potential to lungs and bones,
more than 10% patients presents with bone
metastasis at the time of diagnosis.
 Location within the bone:
Mid-diaphysis(33%)
Metadiaphysis(44%)
Metaphysis(15%)

40.  Pain & swelling of the affected area.
 May also have systemic symptoms:
-fever.
-Anemia.
-Weight loss.
 Pathological fracture(may be present)

41.  Large destructive lesion with an ill-defined,
permeative(76%) appearance.
 Lesion may be purely lytic or lytic and sclerotic
mixed(40%).
 Disruption of cortex and cortical saucerisation is
an early and characteristic sign.
 Laminated, onion skin/onion peel periosteal
reaction(40%).
 Pathological fracture(5%).
 Occasional features: Codman triangle,
spiculated/sun burst periosteal reaction.

42. Plain x-ray left leg
shows-
 Large lytic lesion in
proximal part of
fibula with bone
destruction.
 Massive soft tissue
mass.
 Small lytic lesion in
metaphysis of tibia.

43. Plain x-ray right leg
shows:
 Cortical
destruction and
saucerisation of
cortex of tibia.
 Periosteal reaction’
 Soft tissue
swelling.

44.  X-ray of an
Ewing
sarcoma
patient
showing
onion skin
appearance .

45.  MRI:
- MRI of bone may reveal marrow
replacement ,cortical destruction with an associated
soft tissue mass.
- MRI is also essential tool for staging and
evaluating response to treatment.
 Other investigations:
-Biopsy and histopathology: to confirm diagnosis.
-Chest x-ray: To detect lung metastasis.

47.  Synovial sarcoma is a rare and aggressive
malignant tumor of soft tissue that begins near
the joint.
 It shows microscopic similarity to synovium
that’s why it was named so.
 Cellular origin of synovial sarcoma is unknown
but it is not synovial cell or any cell involved in
the synovium.(So this name is a misnomer).
 More than 90% cases of synovial sarcoma has
chromosomal translocation t(X;18)

48.  More common in young adults(15-40 years)
 Slight male predilection.
 Common sites:
-Around knee, ankle & hip joints.
-Around shoulder, and elbow joints.
 Usually presents with growing mass in proximity
to joint that may be painful or painless.
 Metastasis to lungs and lymph nodes is common.

49. Radiographic feature:
 May be normal findings in about 50%
cases.
 Soft tissue mass having calcification(30%)
 Cortical bone erosion may be seen(5%).
 Periosteal reaction(10-20%)

50. Plain x-rat left arm
showing:
 Lytic lesion in distal
part of radius.
 A soft tissue mass in
dorsal aspect of
forearm having faint
linear calcification.

51.  MRI: It is the modality of choice for tumor
staging.
 Biopsy and histopathology: Synovial sarcoma
shows a biphasic appearance with 2 typical cell
types-spindle cells & epithelial cells.
 Treatment: Wide resection with adjuvant
radiotherapy.

52. Topic Osteosarcoma
Chronic
osteomyelitis
Ewing’s
sarcoma
Synovial
sarcoma
Age
Double peak
(1st at 10-14
years & 2nd
after 65 years)
More common in
41-50 years
5-25 years peak
at 15 years.
Adolescen
t and
young
adult.(15-
40 years
Predisposition
Radiation
therapy, paget’s
disease,
Retinoblatoma,
Li-fraumeni
syndrome,
Rothmund
Syndrome,
Bloom
Syndrome
Recent trauma,
surgery, Diabetes,
sickle cell disease,
IV drug users,
Peripheral
neuropathy,
Immunocomprom
ised individuals
Chromosomal
translocation
t(11:22) in
about 85%-95%
cases
Chromoso
mal
translocati
on t(X:18)
in about
90% cases

53. Topic Osteosarcoma
Chronic
osteomyelitis
Ewing’s sarcoma
Synovial
sarcoma
Location
within the
bone
Metaphyses
(90%)
Diaphyses
(10%)
Metaphyses
Mid-diaphysis(33%),
Metadiaphysis(44%),
Metaphysis(15%)
Not within
the bone
Soft tissue
involvement
Extensive Less or no Extensive Extensive

54. Topic Osteosarcoma
Chronic
osteomyelitis
Ewing’s
sarcoma
Synovial
sarcoma
Aggressiveness
Very
aggressive
Not so
Very
aggressive
Aggressive
Fever, Malaise
& other
constitutional
syndrome
Not common Less common Very common Not common
Metastasis Lungs, Bones No Metastasis Lungs, Bones
Lungs, Lymph
nodes

55. Topic Osteosarcoma
Chronic
osteomyelitis
Ewing’s
sarcoma
Synovial
sarcoma
Radiological
findings
Moth eaten or
permeative
pattern bone
destruction.
Sclerotic/lytic/
mixed lesion.
Aggressive
periosteal
reaction:
Sunburst
appearance,
Codman’s
triangle.
Large soft
tissue shadow
is usually
present.
Pathological
fracture may
be present.
Bony lucency,
sclerotic rime
and cortical
thickening,nho
mogenous
osteoslerosis.
Cortical
thickening.
Reduced bone
density.
Cloaca may be
present.
Soft tissue
swelling may
be present.
Periosteal
reaction may
be found.
Large
destructive
lesion with ill-
defined,
permeative
appearance.
Lesion may be
purely lytic or
mixed.
Disruption of
cortex and
cortical
saucerisation.
Onion skin
periosteal
reaction.
Pathological
fracture.
Codman’s
triangle.
May be normal
findings in
about 50%
cases.
Soft tissue
mass having
calcification(30
%)
Cortical bone
erosion may be
seen(5%).
Periosteal
reaction(10-
20%)

56. Topic Osteosarcoma
Chronic
osteomyelitis
Ewing’s
sarcoma
Synovial
sarcoma
Biopsy and
histopathology
1. Tumor cells
show
significant
atypia and
produce lacey
osteoid.
2. Stroma cells
show
malignant
charecterstics.
No nuclei in
osteocytes with
fibrosis of
marrow and
chronic
inflammatory
cells
Sheets of
monotonous
small round
blue cells with
prominent
nuclei and
minimal
cytoplasm.
Synovial
sarcoma shows
a biphasic
appearance
with 2 typical
cell types-
spindle cells &
epithelial cells
Treatment
Neoadjuvant
chemotherapy,
then limb
salvage
surgery,
adjuvent
chemotherapy
Antiobiotics.
Sequestrectomy
& saucerisation
Induction
chemotherapy
then local
control by limb
salvage
surgery &
radiotherapy
followed by
chemotherapy
Wide resection
with adjuvant
radiotherapy

57. 1. Yochum and Rowe’s ESSENTIALS OF SKELETAL
RADIOLOGY.
2. Textbook of RADIOLOGY AND IMAGING by
David Sutton.
3. Brant and Helm’s FUNDAMENTALS OF
DIAGNOSTIC RADIOLOGY.
4. Grainger & Allison’s Diagnostic Radiology.
5. Core Radiology-A Visual Approach to Diagnostic
Imaging.
6. pubmed.ncbi.nlm.nih.gov
7. Orthobulets.com
8. Radiopedia.com