What is the most common benign bone tumour?
What does an osteochondroma produce?
Bony outgrowth on the external surface of bone which is covered with a cartilaginous cap
Where do osteochondromas typically affect?
Epiphysis of long bones - most common around the knee
What are the negative effects of an osteochondroma?
They are usually asymptomatic and incidental findings
They may produce local pain
There is a small risk of malignant transformation
Any osteochondroma growing in size or producing local pain will be treated in what way?
Multiple osteochondromas may be associated with what?
Underlying genetic disorder
What is an enchondroma?
An intramedullary metaphyseal (usually) cartilaginous tumour
What is the usual appearance of an enchondroma?
May undergo mineralisation and have a sclerotic appearance
What are the usualy symptoms of an enchondroma?
Usually asymptomatic, but can weaken bones resulting in pathological fracture
Where do enchondromas typically affect?
Small tubular bones of the hands and feet
Given the benign nature of enchondromas, what is the treatment?
Currettage - they can be scraped out of bone
What is a simple bone cyst?
A solitary unicystic fluid filled neoplasm
What is the most probable cause for a simple bone cyst?
Growth defect in the physis
Where are simple bone cysts most commonly found?
Metaphyseal in long bones
They can also occur in the talus or calcaneus
What are the most common symptoms of a simple bone cyst?
May lead to weakness and pathological fracture
What is the treatment for a simple bone cyst?
Curettage and bone grafting
Stabilisation may be required
What is an aneurysmal bone cyst?
A lesion of bone containing many blood/serum filled chambers
The formation of aneurysmal bone cysts is thought to be down to what?
Small arteriovenous malformations
Where are aneurysmal bone cysts most commonly found?
- Metaphyses of long bones
- Flat bones (ribs, skull)
- Vertebral bodies
What are the normal symptoms of an aneurysmal bone cyst?
- Pain (due to cortical expansion and bone destruction)
- Pathological fracture (due to bone weakness)
What is the treatment for an aneurysmal bone cyst?
- Curettage and grafting
- Bone cement
Giant cell tumours of bones have a predilection for which long bone regions?
- Can extend as far as subchondral region beside the joint
Where do giant cell tumours most commonly occur in bones?
Around the knee and in the distal radius
(can also occur in other long bones, pelvis and spine)
Why are giant cell tumours of bone often painful?
They are locally destructive to the cortex
They weaken bone and may cause pathological fracture
In terms of causation of the condition, how are giant cell tumours of bone characterised?
A translocation between chromosomes 1 and 2
What is the characteristic appearance of giant cell tumours on x-ray?
Despite being benign, where can giant cell tumours of bone metastasize?
Causes benign pulmonary giant cell tumour
(this occurs in 5% of cases)
What is the treatment for giant cell tumour of bone?
The use of phenol, bone cement or liquid nitrogen to destroy an remaining tumour
Aggressive lesions may need joint replacement
What is fibrous dysplasia?
A disease of bone resulting from a genetic mutation that causes lesions of fibrous tissue and immature bone
Which age group of patients is fibrous dysplasia most likely to affect?
Where are the most frequent sites for fibrous dysplasia?
Head and neck
What is the the underlying cause of fibrous dysplasia?
A genetic mutation causes an abnormality in protein in G protein signalling
Patients with polyostotic fibrous dysplasia have other symptoms involving which type of disorders?
Angular derformities with affected bone being wider with thinner cortices are as a result of what?
Defective bone mineralisation
Why may stress fractures occur in patients with fibrous dysplasia?
The bone is weakened due to defective mineralisation
Extensive involvement of the proximal femur in a patient with fibrous dysplasia causes which chracteristic deformity?
Shepherd's crook deformity
Which medication may help to reduce pain in patients with fibrous dysplasia?
How are pathological fractures stabilised in patients with fibrous dysplasia?
- Internal fixation
- Cortical bone grafts
Why is intralesional excision not generally used for fibrous dysplasia?
It has a high recurrence arte
What is an osteoid osteoma?
A small nidus of immature bone surrounded by an intense sclerotic halo which secretes prostaglandins causing great pain
In which age group do osteoid osteomas most commonly affect and where in the body do the usually affect?
Proximal femur, diaphysis of long bones, vertebrae
What is the predominant clinical feature of osteoid osteoma?
Constant pain, worse at night
Classically, the pain from an osteoid osteoma is greatly relieved by what?
Which two non-invasive tests can confirm the diagnosis of an osteoid osteoma?
- Bone scan
What is the treatment for osteoid osteoma?
What is a Brodie's abscess?
An intraossoeus abscess as a result of subacute osteomyelitis
This is usually as a result of S. aureus infection
This can present as a lytic lesion of bone
Brown tumours are a result of what, and how do they appear on X-ray?
Lytic lesions of bone
Malignant primary bone tumours are most common which age?
Younger age groups
Bony lesions usually relate to ___________
Bony lesions usually relate to metastasis
Metastatic cancer of bone tends to produce _________ pain which is usually worse ____ _________
Metastatic cancer of bone tends to produce constant pain which is usually worse at night
Which generalised systemic symptoms may be present with metastatic bone cancer?
- Loss of appetitie
- Weight loss
What is the most common form of primary bone tumour?
What is an osteosarcoma?
A malignant bone tumour producing bone
The majority of osteosarcoma cases are asscociated with a mutation in which gene?
Retinoblastoma gene (a tumour suppressor)
In which age of patient and location of the body are osteosarcomas most common?
Most commonly the knee
(can also be the proximal femur, proximal humerus and pelvis)
Metastasis of an osteosarcoma via the blood is relatively ___________ and spread via the lymph nodes is __________
Metastasis of an osteosarcoma via the blood is relatively common and spread via the lymph nodes is rare
10% of patients with osteosarcoma have which type of mestastasis upon diagnosis?
In a patient with osteosarcoma, how may lifespan be prolonged?
What is a chondrosarcoma?
A cartilage producing primary bone tumour
In which age group is a chondrosarcoma more common?
Older (mean age 45)
Chondrosarcomas tend to be very ________ and _______ to metastasise
Chondrosarcomas tend to be very large and slow to metastasise
Where are chondrosarcomas most commonly found?
Pelvis or proximal femur
What is the treatment for chondrosarcoma?
Radiotherapy and chemotherapy are not suitable
What is Ewing's sarcoma?
A primary bone tumour with an uncertain cell origin that is most common in teenagers
Where do Ewing's sarcomas most commonly manifest?
Long bones - especially the femur
How are Ewing's sarcomas characteristically described radiologically?
As having an "onion skin" pattern
Tumours such as Ewing's sarcoma are part of a group of tumours described as what?
Small round blue cell tumours
Ewing's sarcoma is associated with the ______ ___________ involving the _______ __________ gene on chromosome ____
Ewing's sarcoma is associated with the t11;22 translocation involving the Ewing's sarcoma gene on chromosome 22
Why may Ewing's sarcoma be misdiagnosed as what and what are the reasons for this?
It presents with:
- Raised inflammatory markers
- Warm swelling in affected area
Ewing's sarcoma tends to be sensitive to which treatments?
The treatment of primary bone tumours usually involves what as well as radiotherapy and chemotherapy (if these are suitable)?
Surgical resection (of tumour and surrounding tissue)
What is required for histological diagnosis and grading of a tumour prior to surgery?
What is lymphoma?
A cancer of round cells of the lymphocytic system and macrophages which can occur as a primary bone tumour from bone marrow or lymphoma may mestastasise to bone
A primary lymphoma of bone is referred to as which type of lymphoma?
Primary lymphoma tends to affect which bones?
Pelvis or femur
What is the treatment of primary lymphoma in bones?
What may be present with metastatic lymphoma?
What is the treatment for metastatic lymphoma?
What is myeloma?
A malignant clonal proliferation of abnormal plasma cells which arises from bone marrow
What is the name of myeloma that presents
a) As a solitary lesion
b) With multiple osteolytic lesions
b) Multiple myeloma
Abnormal cells in myeloma cause deposition of what type of protein and what is this process called?
Abnormal plasma cells deposit defective imunnoglobulin, this is known as amyloidosis, and more specifically AL amyloid as the deposited protein is the immunoglobulin light chain
What is the typical age group of patients with myeloma?
How may patients with multiple myeolma present?
- Back pain
- Bone pain
- Weight loss
- Anaemia and recurrent infection (due to bone marrow supression)
Diagnosis of myeloma often requires what?
Plasma protein electrophoresis
(shows paraprotein - monoclonal immunoglobulin or light chain)
Early morning urine collection for Bence Jones protein assay
Why may metastases of myeloma not be picked up on a bone scan?
There is not usually an osteoblastic response to the osteoclastic response
What is the treatment for:
b) Multiple myeloma
Name the top 5 primary malignant tumours which most commonly mestastasise to bone
- Breast cancer
- Prostate cancer
- Lung cancer
- Renal cell cancer
- Thyroid cancer
(adenopcarcinoma of the colon, bladder cancer and melanoma can rarely metastasise to bone)
Describe how breast cancer metastases appear in bone
Blastic (sclerotic) or lytic
How do prostate cancer metastases appear in bone?
Why are pathological fractures more likely to heal in prostate cancer metastases to bone?
There is high osteoblastic activity so sclerotic masses are quickly produced
Which two therapies can reduce likelyhood of bony metastases in prostate cancer?
- Hormonal therapy
Lung cancer gives rise to what type og bony metastases in bone?
Lytic bone tumours
(mean survival is just 6 months when these are present)
Renal cell carcinoma ausually gives rise to which type of bone metastases?
Large and very vascular lytic "blow out" bony metastases
Why may surgery of biopsy be an issue with renan cell carcinoma metastasis to bone?
It can cause severe bleeding
What is the treatment for renal cell carcinoma with one bony metastasis?
Resection (nephrectomy) - can be curative
Which bones are most frequently implicated in bony metastases?
- Long bones of the lower limb
Fractures or impending fractures as a result of bony metastases are treated in what way?
Stabilisation using long rods and intramedullary nails
Painful lesions thought to be at risk of causing fractures can be treated in which ways?