MSK - Aggressive Bone Tumours Flashcards
tWhat are ChondroBlastomas
What age group?
What distribution?
Children and adolescents
Arises from growth plates (epiphysis)
Mostly in long bones of leg and knee (commonly proximal tibial epiphysis)
**-Lucent lobulated lesion with thin sclerotic margin **
Can cross the growth plate
-Can have calcification associated with it
-Can have surrounding oedema
NOT T2 bright
Adult version is clear cell chondrosarcoma
What are features of Osteosarcoma?
What age group does primary occur in?
Bone forming tumours that can be either primary or secondary
Will have osseous matrix
Painful mass with fever
Primary: -usually in young adults (10 - 20 years) as growth centres are more active during this age
-predilection for either proximal tibia or distal femur
Diagnosis:
- bimodal age distribution in adolescents (10-20 years) and in elderly patients
- bone tumour with osteoid matrix, permeative growth and non-expansile cortical destruction
- location in a metaphyseal-diaphyseal region with epiphyseal extension
80% of osteosarcomas are INTRAmedullary
Osteosarcoma mets to the lung are a cause of occult Pneumothorax
Who gets secondary osteosarcoma?
What are associations?
What is needed to stage?
Occur in elderly
Due to malignant degeneration of pre-existing bone lesions
-Pagets
- Bone infarct
- Osteochondroma
- Osteoblastoma
- Radiotherapy change
Appear as agressive lesions with sunburst periosteal reaction and fluffy cloud like osseous matrix
Staging
- MRI of affected bone (to look for other lesions)
- Bone scan
- CT Chest
Tissue biopsy
What is most common malignant primary soft tissue tumour in over 50’s?
Malignant fibrous histiocytoma (Undifferentiated Pleomorphic Sarcoma)
—Most common type of soft tissue sarcoma—-
Painless soft tissue mass which enlarges over months
Plain film: partly calcified soft tissue mass with cortical erosion of underlying bone
High T1
High T2
Risk Factors:
Radiotherapy
Pagets Disease
What causes sclerotic mets?
bone
Prostate (most common)
Breast (mixed lytic and sclerotic)
Transitional Cell Carcinoma
Lymphoma
Mucinous adenocarcinomas (colon, gastric, ovary)
Medulloblastoma
Neuroblastoma
Carcinoid
What is codman triangle?
Where layers of agressive new bone form rapidly, breaking through the cortex and displacing the periosteum.
Periosteum doesnt have enough time to ossify completly with the new bone formation so only edge ossifys
This creates a triangular shape of codmans triangle
Parosteal vs Periosteal Osteosarcoma
Parosteal - posterior distal femur
Periosteal - medial distal femur
Osteosarcoma Summary
What are Chondrosarcomas?
Where do they appear?
What age group?
Malignant cartilaginous tumours
Seen in older adults
(can develop secondary to Pagets)
Usually found in the long bones
RIng and arcs chondroid matrix with calcifications. Popcorn calcs can also be appearance
Presentation can be with pain/pathological fracture
Where are Chordomas typically located?
Usually in adults
Younger adults - at clivus
Older adults - in sarcum
Most common primary tumour in spine - usually at C2
Will always be in a central position
T2 Bright
Epiphyseal Lucent Bone Lesions
AIG Company
ABC
Infection
Giant Cell (epiphyseal with ECCENTRIC position which means its lateral in position. Can move from epiphyseal to metaphyseal. SOAP Bubble is characteristic)
Clear cell chondroSARCOMA (malignant and has variable appearance)
These bones will all have same lesions as epiphysis - carpals/patella/calcaneus/greater trochanter
Why do Mets and infection tend to go for the metaphysis?
Excellent blood supply
Most of the cystic bone lesions can also occur in Metaphysis
Most entites can occur in diaphysis also
Fibrous dysplasia
What is appearance?
Is there periosteal reaction?
Classically long lesion in a long bone with ground glass matrix
No periosteal reaction and NO pain
Favours the:
-ribs
-long bones
-if it occurs in the pelvis it will also effect the ipsilateral femur giving the shepherds crook deformity
Can be Polyostotic or Monostotic
If Monostotic - usually older patients in 20’s and 30’s
Polyostotic - less than 10 years old usually
*Think of syndromes when you see polyostotoic
Non-ossifying fibroma
Seen in children
Spontaneously regress
Osteoclastic rich benign tumours
Tend to be located in the metaphyses of long bones
DO NOT TOUCH LESION
Lucent lesion with a thin sclerotic rim
What is vertebral plana?
What are 4 most common causes?
This is complete loss of height of vertebral body aka compression fracture
Common causes = MELT
Mets/Myeloma
Eosinphilic granuloma
Lymphoma
Trauma/TB
What age group to think of Eosinophilic granuloma (part of LCH)?
Think of this in every differential for patient under 30 with bone lesion
-Variable appearance
Common presentations
- Vertebral plana in a child
- Skull with lucent bevelled edge lesions
- Jaw
Bone Lesions affecting the calcaleus
Calcaneus can be thought of as a long bone - this makes it easier to define lesions
What are the epiphyseal/metaphyseal and diaphyseal predominant lesions?
Epiphysis
*Chondrobastoma - favours superior epiphysis
Osteoid Osteoma - favours superior epiphysis*
Giant cell tumour - favours epiphysis but typically starts in metaphysis and grows in
Metaphyseal Lesions
Posterior meta-epiphyseal region (towards back of calcaneus)
Mets
Osteomyelitis
Diaphyseal Lesions
Bone cyst (sharp edges. thick sclerotic rim)
Intraosseous lipoma (can have central calcification)
Pseudocyst (is just normal variation in trabecular pattern -
Bone Lesions summary card
Malignant fibrous histiocytomas (Pleomorphic undifferentiated Sarcoma)
What are features?
Soft tissue tumours mostly originating in soft tissue but can originate in bone
Most common soft tissue sarcoma
-Older patients
-Proximal upper limbs and proximal lower limbs
-Can haemorrhage spontaneously
-Can occurs secondary to radiotherapy or pagets
Usually large and aggressive at presentation
Dark to intermediate on T2 (can be bright)
Synovial Sarcoma
What are the features?
Seen in peripheral lower extremeties of patients aged 20 - 40 years foot/ankle/knee
-Never involve the JOINT but can attack bone
-Bakers cyst can be mistaken for this mass
-Will have the TRIPLE SIGN - high/med/low T2 MRI signal all in the same mass
-Fluid fluid levels within the mass
-Small and slow growing (sometimes over years!!)but are malignant
*Ball like tumour in the extremity of a young adult
Soft tissue tumour in the foot of a young adult
BOTH SUGGEST THIS DIAGNOSIS*
Low T1
High T2
Lipoma vs Liposarcoma
Lipomas on ultrasound tend to be either isoechoic or hyperechoic but can be hypo
Lipomas usually superficial
**If there is heterogenous echotexture of anything more than minimal flow or large size = think about Liposarcoma **
Liposarcoma
Most commonly seen in the thigh or retroperitoneum
-*Rare in children
-Usually inadults between 40 - 60 years
-can have solid components over 20 HU
-mixed fatty and solid
-mixed fatty and cystic*
THings that might suggest Liposarcoma
-high amounts of soft tissue
-poor definition of adjacent structrures
-infitration
-calcification
Atypical liposarcomas are low grade and they can be completely fat but contain septations or invade adjacent structures
Liposarcomas tend to be DEEP
What is most common Liposarcoma in patients under 20 years?
What is common pitfall?
Myxoid Liposarcoma
Appear as low T1 and bright T2
Don’t fall into trap of calling them cystic - they need post contrast imaging
-usually in lower extremeties, thigh, buttock, ankle
What is Mazabraud Syndrome?
Rare disease
Polyostotoic fibrous dysplasia and intramuscular myxomas
Soft tissue tumour treatment summary
DONT TOUCH LESIONS
What is osteitis condensans?
Triangular sclerosis in the ilium
Usually bilateral
Seen in pregnant women
