Transcript Sacral lesions – an orthopaedic perspective

Osteosarcoma
Clinical and Imaging
• 5% of primary malignant spinal
tumours
• 4th decade (older than long bone)
• Associated with Paget’s, DXRT
• Mixed lytic / sclerotic appearance
• Aggressive, soft tissue extension
• Osteoid mineralisation
CT
T1W
T1W
T2W
Differential diagnosis
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Ewings
Chondrosarcoma
Metastasis
Osteoblastoma
Lymphoma
SBTR 4346, AB
22M
7/12 Hx LBP
2/12 Hx right leg /
foot pain and
weakness
more recently
urinary problems
4346, Ant Bishop, 22M
Ewing’s sarcoma
• Bone or soft tissue
• Now accepted to be primitive
neurectodermal tumour
• Includes Ewing, PNET, peripheral
neuroepithelioma, Askin tumour
• t (11;22)(q24;q12) and other
rearrangements
PAS
Translocation
Fusion gene
Chimaeric
protein
Control
Control sequence
sequence
Overexpression of
target gene
ES Cytogenetics
t(11,22)(q24;q12) (95%) EWS/FLI1
t(21,22)(q22;q12) (5%)
EWS/ERG
t(7,22)(p22;q12)
EWS/ETV1
t(17,22)(q21;q12)
EWS/EIAF
t(2,22)(q33;q12)
EWS/FEV
inv(22)(q12;q12)
EWS/ZSG
t(16,21)(p11;q22)
FUS/ERG
Ewing’s sarcoma
Clinical and Imaging
Usually 10 – 30yrs
>50% metastases at presentation
Metastatic involvement more common than primary
Permeative pattern of bone destruction
Large soft tissue mass and infiltration
No matrix mineralisation but reactive sclerosis
MR – inhomogeneous, haemorrhage & necrosis
T1W
Differential diagnosis
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Osteosarcoma
Osteoblastoma
Lymphoma
Langerhans
T2WGRE
30F, LBP
30F, LBP
T1W
T2W
Giant Cell Tumour
Clinical and Imaging
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>60% of primary benign sacral tumours
3rd – 5th decades, 2F:1M
Locally aggressive, 12-50% recurrence rate
Lytic, expansile, absent matrix,
+/- cortical breakthrough
CT / MR may show fluid-fluid levels
MR – low signal on T2W due to collagen, high
cellularity and haemosiderin from haemorrhage
Can undergo sarcomatous degeneration
Differential diagnosis
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Expansile metastasis
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Chordoma
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Myeloma
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Aneurysmal bone cyst
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Osteoblastoma
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Brown tumour of hyperparathyoidism
DH, SBTR 4513
Mid thoracic
pain
Myeloma
Clinical
Proliferation of malignant plasma cells
Most common primary bone malignancy
Most common in 6th and 7th decades
Plasmacytoma usually precedes myeloma
Differential diagnosis
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Metastases
Lymphoma
Sarcoma
Chordoma
GCT
Patterns on T1W - Myeloma
Normal
<20% plasma
cells
Infiltration
20 – 50%
plasma cells
Replacement
>50%
plasma cells
Baur-Melnyk. Role of MRI in multiple myeloma. EJR 2005; 55:56
MC, 1907806113
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30F
Left neck pain
Prominent ECA / pulsatile mass
?carotid body tumour
Eosinophilic Granuloma
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5 – 10yrs
15% axial skeleton
Can be asymptomatic
Vertebral body
Multifocal in 10%
Differential
• Ewing’s
• Metastatic neuroblastoma
• ABC
60F, LBP
Haemangioma
Haemangioma
56F, right L5 sciatica
Pagets – later phase
Paget’s disease of bone
• increased bone turnover
osteoclastic and osteoblastic activity
• age > 40 M>F
• 3% of routine autopsies
• aetiology unknown ? viral
racial predilection
• monostotic or polyostotic
• raised alkaline phosphatase
• complications fracture deformity and sarcoma
22F, Indian
Differential diagnosis
Sarcoma
Eosinophilic granuloma
GCT
Lolge S. Isolated solitary vertebral body tuberculosis. Clin Rad 2003
Summary: Imaging
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In children / adults, metastases most frequent bone tumour.
Patient age, location and relative frequency important
In sacrum , Paget’s, chordoma and GCT
Scintigraphy mainly for staging metastatic disease
CT - optimal imaging technique for osteoid osteoma
CT - bony detail , mineralisation, cortical shell & sequestra
CT - often complementary to MRI.
MRI - imaging method of choice.
SBTR 4319
Wal Miller
chondrosarcoma
grade 3
GJ, SBTR 4530
LBP,
Osteoblastoma