Bone Tumours Flashcards
Briefly explain the normal anatomy of long bones
Ends of the bones are called epiphysis, the long middle part is the diaphysis. The ends of long bones have spongey bone called cancellous bone. In the centre is the medullary cavity and the outside of the bone is covered by compact bone.
Briefly explain the normal cells of bones and their function
- Osteoblasts: Bone forming cells.
- Ostocytes: Mature bone cells.
- Osteoclasts: Bone reabsorbing cells.
- Bone matrix which consists of collage, ground substance and calcium hydroxylapatite
What are the two types of bone?
- Mature lamellar bone (normal bone of mature skeleton which can be compact or cancellous)
- Immature woven bone which can be seen in foetus, fractures and bone tumours.
Name examples of secondary tumours and primary bone tumours.
Secondary bone tumours - Metastasis. Very common and almost always come from: Bronchus, breast, prostate, kidney and follicular thyroid cancer. In children likely come from neuroblastoma or rhabdomyosarcoma.
Primary bone tumours - Myeloma, benign tumours eg, osteoid osteoma, chondroma or osteocartilagenous exotosis, and malignant eg, osteosarcoma, chondrosarcoma and Ewing’s tumour.
What are the effects/presentation of bone metastasis?
- Often asymptomatic,
- Bone pain,
- Bone destruction,
- Pathological fractures in long bones,
- Spinal mets can cause vertebral collapse, cord compression, nerve root compression and back pain,
- Hypercalcaemia (extreme thirst and abdominal pain)
What is the best method of detecting bone mets and the two types of bone mets?
PET CT is the gold standard, it detects metabolically active tissue.
Bone lesions are either lytic (bone destruction caused by cytokine release from tumour cells stimulating osteoclasts) or sclerotic (bone forming). Majority are lytic which can be treated with bisphosphonates
What tumours are likely to cause sclerotic metastases?
Prostatic carcinoma, breast carcinoma or carcinoid tumours. They cause reactive new bone formation.
If there is a solitary bone metastases, what are you thinking the primary tumour is?
- Renal or thyroid carcinomas.
- Possible to cure via surgery and there is good prognosis
Describe features of myeloma (in context of bone malignancy)
- Commonest primary malignant tumour of bone (also haematological). There is monoclonal proliferation of plasma cells which if forma a solitary lesion are called a plasmacytoma, if form multiple lesions then is called multiple myeloma
What are the clinical effects of myeloma?
- Bone lytic lesions (can cause pain and fractures)
- Marrow replacement leading to anaemia, leucopenia - infections and thrombocytopenia - bleeding.
- Immunoglobulin excess which cause a monoclonal band on electrophoresis and Bence Jones proteins in urine (immunoglobulin light chains).
- In normal reactive plasma cells there will be mixture of kappa and lambda light chains but in myeloma it will either be all kappa or all lambda.
Describe features of osteoid osteoma, diagnosis and treatment
It is a small, benign osteoblastic proliferation. Especially common in adolescence. Commonly occurs in long bones and spine, it presents with pain worse at night which is relieved by aspirin but not paracetamol, and scoliosis.
Diagnosis - X ray with presence of Nidus (tumour surrounded by sclerotic bone)
treatment - radiofrequency ablation
Describe features of an osteosarcoma?
Highly malignant tumour of cells which form osteoid or bone with haematogenous spread. Commonly occurs in adolescence with second peak in adult hood. Commonly affects metaphysis of long bones.
Presentation - Bone pain, swelling and pathological fractures.
Explain the diagnosis and treatment of an osteosarcoma?
Imaging with X-ray. There will be a destructive lytic lesion with Codman Triangle (formation of new cortex due to tumour lifting off the old cortex as it grows quickly out of the old cortex).
Treatment is via 8 weeks of neoadjunctive chemo followed by resection, further chemo and maybe radiotherapy.
Describe features of osterocartilaginous exostosis
- Benign outgrowth of cartilage with endo-chondral ossification. Very common in adolescence in metaphysis of long bones.
- Occasionally caused by multiple-diaphyseal aclasis (hereditary multiple exostosis)
- Treated via surgical resection
Describe features of an enchondroma
- Benign lobulated mass of cartilage within medulla of bone. It can occur at any age and often affects hands, feet and long bones.
- Present with pain and pathological fractures but often asymptomatic in long bones.
- Treated via curettage
