Benign bone tumours Flashcards
Commonest benign bone tumour
Osteochondroma
Describe an osteochondroma
Bony outgrowth on the external surface with a cartilaginous cap.
What symptoms do osteochondromas cause?
Sometimes localised pain. Sometimes asymptomatic.
Metastatic properties of osteochondromas?
Only a very small 1% chance of metastases.
Under what conditions would you perform an excisional biopsy on an osteochondroma?
If it changes in size or produces pain.
Multiple osteochondromas?
Rare autosomal dominant hereditary disorder.
Enchondroma decription
Usually metaphyseal (narrow part of the bone between the epiphysis and the diaphysis (shaft)) cartilaginous tumour.
What is enchondroma caused by?
Failure of normal enchondral ossification at the epiphyseal growth plate.
Appearance of enchondroma on Xray
Usually lucent (area that is dark on the Xray) but can undergo mineralisation to produce a patchy sclerotic appearence.
Symptoms of enchondroma
Usually asymptomatic and only found incidentally.
However they can weaken the bone resulting in pathological fracture.
Where is an enchondroma likely to occur?
Femur, tibia, humerus, small bones of the hands and feet.
Treatment of enchondroma
If fracture has occured- wait for it to heal and then curretage (scrape it out) and filled with a bone graft to strengthen the bone.
Describe a simple bone cyst
Single cavity benign fluid filled sac in the bone.
Cause of simple bone cysts
Probably due to a growth defect in the physis and therefore occur in the metaphyseal region in long bones e.g. proximal humerus and femur.
Symptoms of simple bone cysts
May be asymptomatic
However can cause weakness leading to pathological fracture.
Treatment of simple bone cysts
Curettage with/without bone strengthening.
Describe an aneurysmal bone cyst
Multi-chambered cyst filled with blood or serum. These chambers can be seen on Xray.
What causes aneurysmal bone cysts?
Thought to be due to small arteriovenous malformation.
Where do aneurysmal bone cysts usually occur?
The metaphyses of many long bones, flat bones and vertebral bodies.
Symptoms/signs of aneurysmal bone cysts?
They are locally aggressive which causes cortical expansion and destruction. This causes pain.
Risk of pathological fracture.
Treatment of aneurysmal bone cysts?
Curretage and bone strengthening.
Describe a giant cell tumour and where it affects?
Locally aggressive tumour which seems to take a liking to the metaphyseal region. Tend to also involve the epiphyses and subchondral bone adjacent to the joint. They occur after the physis have fused and destroy cortex.
Which bones do GCTs affect?
Around the knee, in the distal radius. Can occur in other long bones and in the spine.
Symptoms of GCTs?
They are painful and can cause pathological fracture.
Histology of GCTs
Multi-nucleate giant cells.
Xray appearance of GCTs
Soap bubble
Metastatic potential of GCT
Considered benign- however 5% can metatasise to the lung.
Treatment of GCT
Intralesional excision with use of phenol, bone cement or liquid nitrogen to destroy remaining tumour material and reduce the risk of recurrence.
Very aggressive lesions with cortical destruction may need joint replacement.
Describe fibrous dysplasia
Genetic mutation results in lesions of fibrous tissue and immature bone.
What does fibrous dysplasia affect?
One bone (monostotic) or multiple (polyostotic)
Appearance of affected bone in fibrous dysplasia?
Defective mineralisation may cause angular deformities. The affected bone may also be wider with thinned cortices.
Involvement of the femur with fibrous dysplasia
Shepherds crook look.
What do bone scans of fibrous dysplasia show?
Intense increase in uptake during development but the lesion usually becomes inactive.
Treatment of fibrous dysplasia
Biphosphonates may reduce pain
Pathological fractures will need internal fixation and cortical bone grafts.
Describe an osteoid osteoma
Small nidus (site of origin) of immature bone surrounded by an intense sclerotic halo.
Who are osteoid osteomas likely to occur in?
Adolescents
Common sites of osteoid osteomas
Proximal femur, the diaphysis (shaft) of long bones and the vertebrae.
Symptoms of osteoid osteomas
Intense constant pain.
Worse at night- due to intense inflammatory response
Treatment of osteoid osteomas?
NSAIDs to reduce pain
May resolve spontaneously over time but could have CT guided radiofrequency ablation
En bloc excision
What other diseases present with a lytic lesion?
Brodie’s abscess and hyperparathyroidism.
