SARCOMAS Flashcards
What are the 2 categories of sarcomas?
Bone sarcomas and soft tissue sarcomas
What are the types of malignant bone tumours?
Osteosarcoma
Chondrosarcoma
Ewing’s sarcoma
What are the types of soft tissue sarcomas?
Liposarcoma
Rhabdomyosarcoma (striated muscle origin)
Synovial sarcoma
Fibrosarcoma
Angiosarcoma
Leiomyosarcoma (smooth muscle origin)
What is the most common type of primary bone cancer in adults?
Chondrosarcoma
What is the most common type of primary bone cancer in children and young adults?
Osteosarcoma
What is the most common primary maligannt bone tumour overall?
Osteosarcoma
What are the types of benign bone tumours?
Osteoma
Osteochondroma
Giant cell tumour
What is an osteoma?
A small, benign overgrowth of bone that most typically occurs on the skull
What syndrome are osteomas associated with?
Gardner’s syndrome (a variant of familial adenomatous polyposis)
What is an osteoid osteoma?
A small osteogenic benign tumour often seen in patients under the age of 30
Arise from osteoblasts
Often occurs in long bones in the diaphysis or metaphysis
Smaller than osteomas ans characterised by the presence of a central core of abnormal bone tissue called osteoid
Presentation of osteoid osteomas?
Constant and progressive pain that is worse at night
Relieved by NSAIDs (this is a diagnostic hallmark due to increased levels of COX enzymes and prostaglandins in the lesion)
What is the most common benign bone tumour?
An osteochondroma
Who do osteochondromas most commonly affect?
Males
<20
What is thought to cause osteochondromas?
Mutations in exostosin genes which encode exostosin proteins which help to synthesise heparin sulphate. This is a protein that regulates the growth of the growth plate
What is an osteochondroma?
A benign bony tumour that starts near the growth plate and it results in an exostosis (lateral bony projection)
Where do osteochondromas most commonly occur?
In the metaphysis of long bones - most commonly the distal femur and proximal tibia
Pelvis
Scapula
What is a giant cell tumour?
A benign but locally aggressive tumour of multi nucleated giant cells (osteoclasts) within a fibrous stroma
Where do giant cell tumours most typically develop?
In the epiphysis of the long bones e.g. distal femur and proximal tibia
Peak incidence for age of giant cell tumours?
20-40
XR sign for giant cell tumours?
Double bubble or soap bubble appearance - this is because it producing lytic lesions
What are the 2 benign bone tumours that arise from osteoblasts?
Osteoblastomas
Osteoid osteomas
What is a nidus?
A disorganised mix of small blood vessels, trabeculae and osteoid
Which bone tumours form a nidus?
Osteoblastomas
Osteoid osteomas
Whats the difference between the nidus in Osteoblastomas and osteoid osteomas?
Large >1.5cm in Osteoblastomas
Small <1.5cm in osteoid osteomas and are often surrounded by a ring of sclerotic bone tissue which produces prostaglandins
Where do Osteoblastomas tend to affect?
The axial skeletal e.g. spine and mandible
Who do chondrosarcomas most commonly occur in?
30-60 year olds
More commonly men
What is the difference between primary and secondary chondrosarcomas?
Primary - typically develop in the centre of metaphysis and diaphysis of long bones
Secondary - develop in periphery of flat bones e.g. scapula and sacrum
What can chondrosarcomas sometimes arise from?
Pre-existing osteochondromas that transform
What are chondrosarcomas?
Malignant bone tumours arising from chondriocytes
What do chondrosarcomas appear as on XR?
Radiolucent area with central flecks of calcification within the medullary cavity
Often described as “moth-eaten cloth”
What is an osteosarcoma?
A malignant bone tumour arising from osteoblasts
Who do osteosarcomas most commonly occur in?
Children and adolescents
Can occur in older adults over 60 as a complication
Risk factors for osteosarcoma in older adults?
Paget’s disease
Pre-existing bone lesions
Radiation exposure
Where do osteosarcomas typically affect?
Metaphysis of long bones where there is rapid bone growth e.g. femur, proximal tibia and proximal humerus
Risk factor for osteosarcoma in children?
Retinoblastoma - as pRB is implicated in osteosarcoma
XR findings of osteosarcoma?
Codman’s triangle
Sunburst pattern
What is Codman’s triangle?
the radiographic appearance of the rim of new subperiosteal bone which forms when a lesion such as a tumour lifts the periosteum away from the bone
Seen in osteosarcoma, ewings sarcoma and subperiosteal abscesses
What is a sunburst pattern on XR seen in osteosarcoma?
This occurs when lesions grow too fast ans the margins are poorly defined with an aggressive periosteal reaction
Who are Ewing’s sarcomas most common in?
Children and adolescents
What do Ewing’s sarcomas arise from?
The cell origin of the sarcoma is unknown but the current theory points to mesenchymal stem cells with the chromosomal translocation t(11;22)(q24;q12) resulting in the EWSR1-FLI1 fusion protein.
Where do Ewing’s sarcoma most commonly arise from?
Most frequently in the long bones and pelvis
XR findings of Ewing’s sarcoma?
An area of bone destruction
Onion-peel pattern
What is the onion skin appearance seen in Ewing’s sarcoma?
When the growth develops in a concentric pattern around the outside of the bone like layers in an onion
How do bone cancers present?
Bone pain
Bone swelling
Pathological fractures
Fever, night sweats, fatigue - more common with maligannt tmors
Referral criteria for suspected bone cancer?
Very urgent direct access XR within 48 for children presenting with unexplained bone pain or swelling. If this suggests a possible sarcoma they need very urgent specialist assessment within 48 hours
If an XR suggests the possibility of a bone sarcoma in an adult then 2WW
Imaging for suspected bone cancer?
Plain XR
CT and MRI of bone
MRI of whole body
Biopsy
Why is a whole body MRI so important following a diagnosis of osteosarcoma?
As these often cause skip lesions
(Also checks for distant metastasis and stages the tumour as with the other types of bone cancers)
Which primary bone cancer has the worst prognosis?
Osteosarcoma - 40% survive 5 years
Characteristic presentation of osteochondroma?
A painless palpable mass or bony protuberance near a joint
Characteristic presentation of a giant cell tumour?
Localised pain and swelling, commonly at the end of a long bone
What is an endochrondroma?
When chondromas occur in the bones of the hands and in the diaphysis/metaphyss of the bone
Characteristic presentation of osteosarcoma?
Aggressive and progressive pain
Pain at night
Characteristic presentation of chondrosarcoma?
Slow growing with dull pain and swelling
Characteristic presentation of Ewing’s sarcoma?
Throbbing pain and swelling
Most commonly tibia, fibula, clavicle or humerus
May be generally unwell with pyrexia, fatigue and weight loss
What is a simple bone cyst?
Fluid-filled holes in bones that commonly agent the diaphysis of long bones
Affect children and adolescents
What is the problem with a simple bone cyst?
They can occasionally cause pathological fractures
How do we manage a simple bone cyst?
Some are asymptomatic and small enough to spontaneously heal as the pt reaches skeletal maturity
In large cysts decompression is important e.g. curettage, grafting, percutaneous aspiration
What are anerysmal bone cysts?
Benign tumours in the bone
Affect children more frequently
They are hollow and filled with cysts making them fragile and prone to fracture
Associated with malignant transformation
