Benign Bone Tumours Flashcards
Describe osteochondroma.
A benign lesion derived from aberrant cartilage from the perichondral ring; the most common benign bone tumour
What is the aetiology of osteochondroma?
- Common in adolescents and young adults (10-20 years)
- Can be caused by trauma
- Can be solitary or multiple
- Multiple osteochondromata can occur as an autosomal dominant hereditary disorder - Multiple Hereditary Exostosis (MHE)
What is the pathophysiology of osteochondroma?
produces a bony outgrowth on the external surface with a cartilaginous cap
What is the clinical presentation of osteochondroma?
- Painless, hard lump
- Commonly occur near the knee - distal femur/proximal tibia
- May be symptoms with activity - pain from tendons, numbness from nerve compression
What is the investigation for osteochondroma?
Imaging (x-ray, MRI) - cartilage capped ossified pedicle
What is seen on this x-ray?
Osteochondroma
What is the management of osteochondroma?
- Close observation - small risk of malignant transformation (<1%) so any lesion growing in size or causing pain may require excision
- In MHE there are more tumours so higher change of malignancy
What is an enchondroma?
Intramedullary and usually metaphyseal cartilaginous tumour caused by failure of normal enchondral ossification at the growth plate; 2nd most common benign bone tumour
What is the aetiology of enchondroma?
Most commonly presents 20-50 years old
What is the typical presentation of enchondroma?
- Can occur in the femur, humerus, tibia and small bones of the hand and feet
- Many are incidental and usually asymptomatic but they can weaken the bone leading to pathological fracture
What are the investigations for enchondroma?
- Imaging - x-ray, further imaging if needed
- Lesion is usually lucent on imaging but can undergo mineralisation with a patchy sclerotic appearance
What is seen on this x-ray?
Enchondroma
What is the management of enchondroma?
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?
Single cavity benign fluid filled cyst in a bone.
What is the aetiology of a simple bone cyst?
Probably a growth defect in the physis and are therefore metaphyseal in long bones (usually in proximal humerus and femur), although they can occur in the talus or calcaneus
What is the presentation of a simple bone cyst?
May be asymptomatic and an incidental finding (usually x-ray of child/YA) but can weaken the bone leading to pathological fracture
What is the investigations of a simple bone cyst?
May be asymptomatic and an incidental finding (usually x-ray of child/YA) but can weaken the bone leading to pathological fracture
What is seen in these images?
Simple bone cyst
What is the management of a simple bone cyst?
Treatment with curettage and bone grafting +/- stabilisation may be required
What is an aneurysmal bone cyst?
Consists of many chambers which are filled with blood or serum
What is the aetiology of an aneurysmal bone cyst?
- Thought to be due to a small arteriovenous malformation
- Can occur in the metaphysis of many different long bones, flat bones and vertebral bodies
What is the pathophysiology of an aneurysmal bone cyst?
The lesion is locally aggressive causing cortical expansion and destruction → pain
What is the typical presentation of an aneurysmal bone cyst?
- Painful mass/swelling
- Pathological fracture
What are the investigations of an aneurysmal bone cyst?
Chambers may be seen on xray
What is seen on this x-ray?
Aneurysmal bone cyst
What is the management of an aneurysmal bone cyst?
Curettage and grafting or use of bone cement
What is a giant cell tumour of bone?
Benign tumour arising from the giant cells of the bone marrow
What is the pathophysiology of giant cell tumour of the bone?
- Occur in the metaphyseal region, tend to involve the epiphysis and can extend to the subchondral bone adjacent to the joint
- Can be locally aggressive
What is the typical presentation of giant cell tumour of the bone?
- Painful mass/swelling
- Commonly occur around the knee and in the distal radius but can occur in other long bones, the pelvis and the spine
- May cause pathological fracture
What is the investigation for a giant cell tumour of the bone?
X-ray - characteristic ‘soap bubble’ appearance
Histology - consist of multi-nucleated giant cells
What is seen on the x-ray?
Giant cell tumour of the bone
What is the management of giant cell tumour of bone?
- 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
- Considered benign but 5% can metastasize to the lung with benign pulmonary GCT
What is fibrous dysplasia?
Benign, developmental disorder of bone that causes normal skeletal tissue to be replaced by fibrous tissue
What is the aetiology of fibrous dysplasia?
- Genetic mutation
- Usually occurs in adolescence
What is the pathophysiology of fibrous dysplasia?
- Genetic mutation results in lesions of fibrous tissue and immature bone
- Can affect one bone (monostotic) or more than one bone (polyostotic)
- Defective mineralisation may result in angular deformities and the affected bone is wider with thinned cortices
What is the presentation of fibrous dysplasia/
- Bone pain and deformities
- Pathological fractures
What are the investigations for fibrous dysplasia?
- Bone scan - show intense increase in uptake during development but the lesion usually becomes inactive
- Extensive involvement of the proximal femur can produce a ‘shepherd’s crook’ deformity on x-ray
What is seen on this x-ray?
Fibrous dysplasia
What is the management of fibrous dysplasia?
- Bisphosphonates may reduce pain
- Pathological fractures should be stabilized with internal fixation and cortical bone grafts used to improve strength
- Simple intralesional excision alone has a very high recurrence rate
What is osteoid osteoma?
Benign bone-forming tumours that typically occur in children
What is the aetiology of osteoid osteoma?
- Most commonly occur in adolescence
- Common sites include the proximal femur, the diaphysis of long bones and the vertebrae
What is the presentation of osteoid osteoma?
- Intense constant pain, worse at night due to the intense inflammatory response
- Pain is greatly relieved by NSAIDs
What are the investigations for osteoid osteoma?
- The lesion may be seen on x-ray however bone scan (intense local uptake) and CT can confirm the diagnosis
- CT: Small nidus of immature (woven) bone surrounded by an intense sclerotic halo (osteoblastic rim)
What is seen on this image?
Osteoid Osteoma
What is the management for osteoid osteoma?
the lesion may resolve spontaneously over time but some cases may require CT guided radiofrequency ablation or en bloc excision
