Bone Tumors: Osteosarcoma, Ewing's, GCT & Metastasis Guide

Bone Tumors

Bone tumors can be primary (from bone) or secondary (metastasis). Diagnosis relies on the patient's age, location of the tumor, and radiological appearance.

1. Common Benign Tumors

• Osteochondroma: Most common benign tumor. Growth of bone capped with cartilage (Exostosis). Grows away from the joint.
• Giant Cell Tumor (GCT): "Osteoclastoma". Locally aggressive.
  • Age: 20-40 years.
  • Location: Epiphysis (after fusion). Knee/Distal Radius.
  • X-ray: "Soap Bubble" appearance. Eccentric lytic lesion.

2. Common Malignant Tumors

• Osteosarcoma: Most common primary malignancy in children/adolescents.
  • Location: Metaphysis (Distal Femur/Proximal Tibia).
  • X-ray: "Sunburst" appearance and Codman's Triangle (periosteal elevation).
• Ewing's Sarcoma: Small round blue cell tumor.
  • Location: Diaphysis (Shaft).
  • X-ray: "Onion Peel" appearance (layered periosteal reaction).
• Metastasis: Most common bone tumor overall (in adults > 40). Sources: Prostate, Breast, Kidney, Thyroid, Lung ("Lead Kettle" mnemonic).

25 Practice MCQs

Q1. The most common primary malignant bone tumor in adolescents is:

Answer: A). Peak age 10-20.

Q2. "Sunburst" appearance on X-ray suggests:

Answer: A). Spicules of bone growing perpendicular to the cortex.

Q3. "Onion Peel" appearance suggests:

Answer: B). Layered periosteal reaction.

Q4. Giant Cell Tumor (GCT) typically occurs in the:

Answer: A). "Epiphyseal" lesion in adults.

Q5. "Soap Bubble" appearance on X-ray is characteristic of:

Answer: A). Expansile lytic lesion.

Q6. Most common site for Osteosarcoma is:

Answer: A). "Away from the elbow, towards the knee".

Q7. Codman's Triangle represents:

Answer: A). Seen in Osteosarcoma and sometimes Ewing's/Infection.

Q8. Osteochondroma is:

Answer: A). Grows away from the joint.

Q9. Ewing's Sarcoma mimics:

Answer: A). Both present with systemic signs.

Q10. Night pain relieved by Aspirin is pathognomonic for:

Answer: A). Small benign tumor with a nidus.

Q11. The most common source of bone metastasis in men is:

Answer: A). Usually blastic (sclerotic) lesions.

Q12. Multiple Myeloma typically presents with:

Answer: A). Older adults.

Q13. Treatment for GCT is:

Answer: A). High recurrence rate.

Q14. Unicameral Bone Cyst (Simple Bone Cyst) usually occurs in:

Answer: A). "Fallen Leaf" sign if it fractures.

Q15. Enneking Staging system is used for:

Answer: A). Based on Grade (G), Site (T), and Metastasis (M).

Q16. Chondrosarcoma is resistant to:

Answer: A). Slow growing, cartilaginous tumor.

Q17. "Shepherd's Crook" deformity is seen in:

Answer: A). "Ground glass" appearance.

Q18. Chemotherapy is crucial in Osteosarcoma to:

Answer: A). Survival improved from 20% to 70% with chemo.

Q19. Aneurysmal Bone Cyst (ABC) is:

Answer: A). Fluid-fluid levels on MRI.

Q20. Limb Salvage Surgery involves:

Answer: A). Standard for most bone sarcomas now.

Q21. Hereditary Multiple Exostoses (HME) carries a risk of:

Answer: A). Patients need monitoring.

Q22. Prostate cancer metastases are usually:

Answer: A). "Ivory vertebra".

Q23. Lung and Breast cancer metastases are usually:

Answer: A). Destroy bone.

Q24. Alkaline Phosphatase is elevated in:

Answer: A). Marker of osteoblastic activity.

Q25. Biopsy of a bone tumor should be done:

Answer: A). Poorly placed biopsy can necessitate amputation.