What is the commonest benign bone tumour?
What is the tumour assocated with osteochondroma?
A bony outgrowth on the external surface with a cartilaginous cap
What symtpoms are associated with osteochondroma?
When should an osteochondroma be excised and why?
Small chance of turning malignant
Should excise if growing in size or causing pain
What is an enchondroma?
An intramedullary and usually metaphyseal cartilaginous tumour
What causes enchondroma?
Failure of normal enchondral ossification at the growth plate
Where do enchondroma tend to occur?
Small bones of hands and feet
What is the appearance of enchondroma on imaging?
Usually lucent but can undergo mineralization with a patchy sclerotic appearance
What is a complication of enchondroma?
Asymptomatic but can weaken bone causing pathological fractures
What is the treatment avaliable for enchondroma and when is it used?
Once a fracture has healed or if there is a risk of impending fracture they may be scraped out (curettage) and filled with bone graft to strengthen the bone
What is a simple bone cyst?
A single cavity benign fluid filled cyst in a bone
Where do bone cysts occur?
Proximal humerus and femur
What is an aneurysmal bone cyst?
A cyst that contains lots of chambers which are filled with blood or serum
Where do aneurysmal cysts occur?
The metaphyses of many different long bones, flat bones (ribs, skull) and vertebral bodies
What are the characteristics of an aneurysmal cyst?
Locally agressive causing cortical expansion and destruction and is usually painful, with an increased risk of pathological fracture
What is the characteristic appearance of a giant cell bone tumour on Xray?
Soap bubble appearance
Where do giant cell tumours of bone tend to occur?
Other long bones
Where in bone do giant cell tumours occur?
Usually metaphyses, but sometimes epiphyses and can spread to subchondral bone
What are the characteristics of a giant cell bone tumour?
Locally invasive, destroying cortex
Can metastasise to lung
Occur after physis has fused
What is the treatment for giant cell bone tumour?
Intralesional excision with use of phenol, bone cement or liquid nitrogen to destroy remaining tumour material and reduce the risk of recurrence
What is fibrous dysplasia?
A disease of a bone usually occurring in adolescence where a genetic mutation results in lesions of fibrous tissue and immature bone
In fibrous dysplasia, what do the bones look like and why?
Defective mineralization may result in angular deformities and the affected bone is wider with thinned cortices
What deformity can occur in extensive involvement of the proximal femur in fibrous dysplasia?
Shepard's crook deformity
What are the complications of fibrous dysplasia?
Deformity of bones e.g. Shepard's crook deformity
What does fibrous dysplasia show on bone scan?
Intense increase in uptake during development but the lesion usually becomes inactive
How is fibrous dysplasia treated?
Bisphosphonates to reduce pain
Pathological fractures should be stabalised with internal fixation and cortical bone grafts to improve strength
What is an osteoid osteoma?
A small nidus of immature bone surrounded by an intense sclerotic halo
At what age does osteoid osteoma tend to occur?
What common sites does osteoid osteoma affect?
The disphysis of long bones
What is the predominant clinical feature in osteoid osteoma?
Intense constant pain, worse at night due to the intense inflammatory response
What signs on Xray indicate a malignant bone tumour?
Aperiosteal reaction (raised periosteum producing bone),
New bone formation (sclerosis as well as lysis from destruction)
Extension into the surrounding soft tissue envelope
What is the most common form of malignant primary bone tumour?
Why is osteosarcoma named as it is?
It is a malignant tumour producing bone
What age groups are most commonly affected by osteosarcoma?
Adolescents and young adults
Where is the most common site of bone involvemnent in osteosarcoma?
60% of tumours involve the knee
What sites can osteosarcoma occur at?
What is the usual form of metastatic spread from osteosarcoma?
What treatment can prolong surivival in osteosarcoma?
What is a chondrosarcoma?
A cartilage producing primary bone tumour and is less common and less aggressive than osteosarcoma
What is the mean age of patient affected by chondrosarcoma?
What are the characteristics of chondrosarcoma?
Very slow to metastasise
What is Ewing's sarcoma?
A malignant tumour of endothelial cells in the marrow
Which type of malignant bone tumour has the poorest prognosis?
At what age to most cases of Ewing's sarcoma occur?
10 - 20
What is Ewing's sarcoma commonly mistaken for and why?
Fever, raised inflammatory markers and a warm swelling