Patient: 62-year-old retired engineer Presentation: 3-month history of progressive right hip and groin pain following a minor fall, now requiring walking stick, night pain disturbing sleep Relevant history: Known enchondroma in proximal right femur monitored with X-rays for 10 years (stable until now), no previous surgery, no other medical conditions, non-smoker, independent mobility prior to current symptoms Examination findings:
| Test | Result | Normal Range | Interpretation |
|---|---|---|---|
| Hb | 128 g/L | 130-170 g/L | ↓ Mildly low |
| WCC | 8.2 ×10⁹/L | 4-11 ×10⁹/L | Normal |
| Platelets | 285 ×10⁹/L | 150-400 ×10⁹/L | Normal |
| CRP | 15 mg/L | <5 mg/L | ↑ Mildly elevated |
| ESR | 28 mm/hr | <20 mm/hr | ↑ Elevated |
| ALP | 165 U/L | 30-120 U/L | ↑ Elevated |
| LDH | 310 U/L | 120-250 U/L | ↑ Elevated |
| Calcium | 2.45 mmol/L | 2.2-2.6 mmol/L | Normal |
| Albumin | 38 g/L | 35-50 g/L | Normal |
| Creatinine | 95 μmol/L | 60-110 μmol/L | Normal |
Image 1: AP and Lateral Radiographs of Right Hip/Proximal Femur
Radiological features:
Image 2: MRI of Right Proximal Femur
Findings:
Image 3: CT Chest (Staging)
Findings:
What is the diagnosis and differential diagnosis?
What is the epidemiology and pathophysiology of this tumour?
What staging investigations would you perform?
How would you manage this patient?
What are the prognostic factors and expected outcomes?
What surveillance is appropriate for patients with enchondromas?
This pattern suggests Dedifferentiated Chondrosarcoma:
Distinguish from Conventional Chondrosarcoma:
| Feature | Conventional | Dedifferentiated |
|---|---|---|
| Appearance | Uniform cartilage pattern | Biphasic (two distinct components) |
| Transition | Gradual grade variation | Abrupt transition |
| Prognosis | Grade-dependent (30-90%) | Uniformly poor (7-18%) |
| Chemo response | None | May respond (high-grade component) |
| Behaviour | Primarily local | Early metastases |
Q: "What is the difference between dedifferentiated and high-grade conventional chondrosarcoma?"
| Feature | Dedifferentiated | Conventional Grade III |
|---|---|---|
| Pattern | Biphasic (two distinct components) | Uniform high-grade cartilage |
| Matrix | Absent in high-grade component | Cartilage matrix present |
| Chemo sensitivity | Partial (high-grade component) | Chemoresistant |
| Prognosis | 7-18% 5-year | 30-50% 5-year |
| Transition | Abrupt | Not applicable |
The key distinction is the abrupt transition between recognisable low-grade cartilage and high-grade non-cartilaginous sarcoma.
Q: "Would you offer chemotherapy to this patient?"
Chemotherapy considerations:
Arguments for:
Arguments against:
Decision: Discuss with patient, offer if good performance status and willing. Consider doxorubicin-based regimen. Realistic expectation is disease stabilisation rather than cure.
Q: "The patient asks about survival. How do you counsel them?"
Approach to prognostic discussion:
Key message: Honest but compassionate communication, focus on achievable goals.
Q: "What reconstruction would you use for proximal femoral resection?"
| Option | Advantages | Disadvantages |
|---|---|---|
| Proximal femoral replacement (megaprosthesis) | Immediate stability, early weight-bearing, predictable | Infection risk, dislocation, implant complications |
| Allograft-prosthetic composite | Bone stock restoration, soft tissue attachment | Nonunion, fracture, longer rehab |
| Intercalary allograft | Biological reconstruction | High complication rate |
| Arthrodesis | Durable if united | Loss of motion, difficult surgery |
For this patient with metastatic disease and limited prognosis: Megaprosthesis - provides rapid rehabilitation and function for remaining life.