Bone Tumours Flashcards
What are the types of bone tumours?
- secondary tumours from metastasis
- myeloma (plasma cell cancer)
- primary bone tumours (rare)
What cancers commonly spread to the bone?
- bronchus
- breast
- prostate
- kidney
- thyroid (follicular)
- childhood: neuroblastoma, rhabdomyosarcoma
What bones are commonly affected with tumours?
- long bones
- vertebrae
haematogenous spread
What are the effects of metastasis to bone?
- can be asymptomatic
- bone pain
- bone destruction
- long bones = pathological fracture (from event that shouldn’t cause a fracture)
- spinal metastases = vertebral collapse, spinal cord compression, nerve root compression, back pain
- hypercalcaemia (from osteoclast activation)
What can be viewed in a PET CT of a bone with a tumour in it?
areas of high metabolic activity
Describe the mechanism of lytic lesions in the bone
- tumour cells stimulate cytokine release which activates osteoclast activity to resorb bone
- inhibited by biphosphonates
What are the common causes of sclerotic lesions?
- prostatic carcinoma
- breast carcinoma
- carcinoid tumour
Describe the mechanism of sclerotic lesions in the bone
- reactive new bone formation
- tumour cells induce cytokines that activate osteoblast activity
What are the common causes of a single bone metastasis and the treatment?
- renal and thyroid carcinomas
- surgical resection
- can be curative
Describe the clinical effects of myeloma
- bone lesions (lytic): can cause pain and fracture
- marrow replacement with plasma cells (anaemia, bleeding and infections)
- immunoglobulin excess (produced by plasma cells)
How can you differentiate between a normal plasma cell reaction to infection vs myeloma?
- in response to an infection, the plasma cells of the bone marrow will produce many different types of immunoglobulin
- in myeloma (clonal disorder), only 1 type of immunoglobulin is present - kappa/lambda
How can you measure immunoglobulin levels?
- serum electrophoresis
- urine (detect immunoglobulin light chains (Bence Jones protein)
What are the consequences of marrow replacement with plasma cells in myeloma?
- pancytopenia
- anaemia
- leucopenia: infections
- thrombocytopenia: haemorrhage
List the primary bone tumours
Benign:
- osteoid osteoma (bone forming)
- chondroma (cartilage forming)
- osteocartilagenous exostosis
Malignant:
- osteosarcoma
- chrondrosarcoma
- Ewing’s sarcoma
Describe the features of osteoid osteoma
- small benign osteoblastic proliferation
- commonly long bones, and spine
- pain which is worse at night and relieved by NSAIDs (not paracetamol)
- if it is near a joint = synovitis
How does an osteoid sarcoma look on imaging?
blacker area with a sclerotic surrounding
Describe an osteosarcoma
- a malignant tumour which cells form osteoid or bone
- metaphysics of long bones, 50% form around the knee
- peaks 10-25y and again in adulthood (esp if Paget’s, previous necrosis or radiotherapy)
- presents with bone pain, swelling and pathological fracture
- non-specific symptoms
What signs can you see on imaging for an osteosarcoma?
- lytic lesion
- cortical destruction with soft tissue mass
- Codman triangle
- sometimes soft tissue mass
What is the treatment for osteosarcoma?
- neoadjuvant chemotherapy
- wide local excision, limb sparing
- further chemotherapy
- +/- radiotherapy for local control
List the cartilaginous tumours
Benign: enchondroma, osteocartilaginous exostosis
Malignant: chondrosarcoma
Describe the features of osteocartilaginous exostosis
- benign outgrowth of cartilage with end-chondral ossification
- derived from growth plate
- common in children
- multiple-diaphysial aclasis (AD)
- long bones
Describe the features of enchondroma
- lobulated mass of cartilage within the medulla
- hands, feet, long bones (asymptomatic in long bones)
- causes swelling and pathological fracture in the hands
- popcorn calcification on imaging
Describe features of chrondrosarcoma
- can be primary, from endochondroma that has transformed, or exostosis
- central in medullary canal or peripheral on bone surface
- axial skeleton, pelvis, ribs, shoulder girdle, proximal femur and humerus
- presents with bone pain, swelling, pathological fracture, neurological symptoms
- popcorn calcifications, lytic lesions, cortical destruction with soft tissue mass
Describe features of Ewing’s sarcoma
- long bones, flat bones or limb girdle
- metastasises early to lung, bone marrow, bone
- micrometastases
- presents with pain, swelling, night sweats, fever, weight loss
- imaging signs show lytic lesion, periostea new bone formation
How is a Ewing’s sarcoma tumour identified?
- translocation between chromosomes 11 and 22
- identified by FISH and PCR
What is the treatment for Ewing’s sarcoma?
- neoajuvant chemotherapy (doxorubicin, cyclophosphamide, vincristine)
- surgery
- more chemo
- +/- radiotherapy
