Orthopaedics
Bone Tumours
Bone tumours for MBBS and NEET-PG: osteosarcoma, Ewing sarcoma, giant cell tumour, osteochondroma and metastases with their classic x-ray patterns, mapped to NMC code OR10.1.
MedNext Academy | 3 min read
Bone Tumours
Bone tumours for MBBS and NEET-PG: osteosarcoma, Ewing sarcoma, giant cell tumour, osteochondroma and metastases with their classic x-ray patterns, mapped to NMC code OR10.1.
This chapter covers benign and malignant tumours of bone. It emphasises pattern recognition from age, the site within the bone and the radiological appearance, contrasts the common primary tumours such as osteosarcoma, Ewing sarcoma and giant cell tumour, and stresses that metastases are the commonest malignant bone lesion in adults.
High-yield: Bone Tumours
- Osteochondroma is the commonest benign bone tumour and appears as a bony outgrowth capped by cartilage.
- A giant cell tumour is a locally aggressive lesion at the epiphysis of long bones, classically the distal femur, with a soap bubble appearance on x-ray.
- Osteosarcoma is the commonest primary malignant bone tumour and typically arises around the knee in adolescents.
- A sunburst pattern and Codman triangle on x-ray suggest an aggressive lesion such as osteosarcoma.
- Ewing sarcoma affects the diaphysis of long bones in children and shows an onion skin periosteal reaction.
- A chondrosarcoma is a malignant cartilage tumour that tends to occur in older adults and in flat bones like the pelvis.
- An enchondroma is a benign cartilage tumour within bone, often found incidentally in the small bones of the hand.
- Multiple myeloma produces punched out lytic lesions in the skull and axial skeleton in older adults.
- Metastases are far more common than primary bone tumours in adults, and the classic sources are breast, prostate, lung, thyroid and kidney.
- Prostate metastases are typically sclerotic, while most other bony metastases are lytic.
- The staging and diagnostic sequence is x-ray, then MRI for local extent, then biopsy, which should be planned by the treating surgeon.
- An osteoid osteoma causes night pain that is characteristically relieved by aspirin or other non-steroidal drugs.
- The site of the lesion within the bone, the age of the patient and the pattern of periosteal reaction narrow the differential of a bone tumour.
- A pathological fracture through a bone lesion should prompt a search for an underlying tumour before it is simply fixed.
Classic tumour patterns
- **Osteosarcoma:** Adolescent, around the knee, metaphysis, sunburst pattern and Codman triangle.
- **Ewing sarcoma:** Child, diaphysis of long bones, onion skin periosteal reaction.
- **Giant cell tumour:** Young adult, epiphysis, distal femur, soap bubble appearance, locally aggressive.
- **Metastases:** Commonest adult malignant lesion: breast, prostate, lung, thyroid, kidney.
NMC competencies in this chapter
- **OR10.1:** Benign and malignant bone tumours: features, diagnosis and principles of management
Frequently Asked Questions
What is the commonest primary malignant bone tumour?
Osteosarcoma. It usually arises around the knee in adolescents and shows aggressive x-ray signs such as a sunburst pattern and a Codman triangle.
How do you tell Ewing sarcoma from osteosarcoma radiologically?
Ewing sarcoma typically arises in the diaphysis with an onion skin periosteal reaction, while osteosarcoma arises at the metaphysis with a sunburst pattern and a Codman triangle.
Why are metastases important in bone tumours?
In adults, secondary deposits are far more common than primary bone cancer, so a lytic or sclerotic bone lesion in an older patient should prompt a search for a breast, prostate, lung, thyroid or kidney primary.
How is a suspected bone tumour worked up?
The sequence is plain x-ray, then MRI to assess local extent, then a carefully planned biopsy, ideally by the surgeon who will treat the tumour so the biopsy track can later be excised.
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