Bone Cancer and Sarcoma Flashcards
What are sarcomas?
Tumours of the body’s supportive connective tissue
What can sarcomas arise from?
- Bone
- Muscle
- Cartilage
- Tendon
- Fat
- Synovial tissue
What % of cancers do sarcomas account for?
Less than 1%
What kind of sarcomas develop primarily in children and adolescents?
- Ewing’s sarcoma
- Osteosarcoma
What does the occurrence of Ewing’s sarcoma and osteosarcoma appear to correlate with?
The growth spurt
Are soft tissue sarcomas common in adults?
No, they are rare in adults
What % of childhood cancers do soft tissue sarcomas account for?
Approx. 6%
What is the aetiology of bone sarcomas?
For the majority of bone sarcomas, no specific aetiology has been established, although predisposing factors have been identified
What group has an increased incidence of osteosarcoma?
Children with familial retinoblastoma
What is the genetic abnormality in children with familial retinoblastoma?
13q chromosome deletion
What are radiation-associated sarcomas?
Sarcomas that develop within a radiation field
When do radiation-associated sarcomas develop?
Usually after a latent period of at least 3 years
Of what type are the majority of radiation-induced sarcomas?
Osteosarcomas
What is osteosarcoma often associated with in adults?
- Underlying bone abnormality, such as Paget’s disease or fibrous dysplasia
- Where the bone has been irradiated previously
What genetic association is there with soft tissue sarcomas?
- Neurofibromatosis type 1
- Hereditary retinoblastoma
- Li-Fraumeni syndrome
What exposures increases the risk of soft tissue sarcomas?
- Previous radiation therapy
- Exposure to chemicals such as vinyl chloride monomers
- Herbicides
Where does Ewing’s sarcoma typically arise from?
Axial skeleton
What genetic mutation is Ewing’s sarcoma associated with?
t(11;22) chromosomal translocation
How does a t(11;22) chromosomal translocation increase the risk of Ewing’s sarcoma?
It juxtaposes the EWS and FL11 genes, producing a hybrid transcript that is able to act as a master regulatory protein
Where do most osteosarcomas occur?
In the metaphyseal region of growing long bones, such as the distal femur, proximal tibia, and proximal humerus
What is Ewing’s sarcoma classically described as?
Classically a diaphyseal lesion
Does Ewing’s sarcoma always arise in the diaphysis?
No, it may arise from any region within an involved long bone
Where does Ewing’s sarcoma commonly arise?
- Flat bones of pelvis
- Scapula
Where are primary bone tumours of any histological subtypes extremely rare?
- Spine
- Sacrum