Patient: 68-year-old man Presentation: Sudden onset left thigh pain after standing from chair, unable to weight-bear, preceded by 6-week history of dull aching left thigh pain Relevant history: 40 pack-year smoking history (stopped 5 years ago), 8kg weight loss over 3 months, decreased appetite, productive cough for 2 months, no prior malignancy diagnosed, retired carpenter (asbestos exposure) Examination findings:
| Test | Result | Normal Range | Interpretation |
|---|---|---|---|
| Hb | 98 g/L | 130-170 g/L | ↓ Anaemia of chronic disease |
| WCC | 11.2 ×10⁹/L | 4-11 ×10⁹/L | ↑ Mildly elevated |
| Platelets | 425 ×10⁹/L | 150-400 ×10⁹/L | ↑ Reactive |
| CRP | 85 mg/L | <5 mg/L | ↑ Elevated |
| ESR | 95 mm/hr | <20 mm/hr | ↑ Markedly elevated |
| Calcium | 2.85 mmol/L | 2.2-2.6 mmol/L | ↑ Hypercalcaemia |
| ALP | 320 U/L | 30-120 U/L | ↑ Elevated (bone/liver) |
| Albumin | 28 g/L | 35-50 g/L | ↓ Hypoalbuminaemia |
| Creatinine | 125 μmol/L | 60-110 μmol/L | ↑ Mild renal impairment |
| PSA | 2.5 ng/mL | <4 ng/mL | Normal |
| Protein electrophoresis | No paraprotein | - | Excludes myeloma |
Image 1: AP and Lateral Radiographs of Left Femur
Radiological features:
Image 2: CT Chest/Abdomen/Pelvis
Findings:
What is your differential diagnosis and most likely diagnosis?
Describe your workup for carcinoma of unknown primary (CUP).
How would you assess the risk of pathological fracture using Mirels score?
How would you manage this pathological fracture?
What is the prognosis and how does this affect your surgical decision-making?
What if this patient had a solitary renal metastasis instead?
This pattern suggests Metastatic Carcinoma:
Common Lytic Metastases (Mnemonic: "Kidney-Thyroid-Lung-Breast-Lick-Bone"):
Common Blastic Metastases:
Q: "What are the most common sites for bone metastases?"
Most common sites (in order):
Metastases occur in red marrow areas due to rich blood supply and Batson's venous plexus.
Q: "When would you consider curative resection for bone metastases?"
Curative resection may be considered when:
Most common scenario: solitary renal cell carcinoma metastasis
Q: "What is the role of radiotherapy in bone metastases?"
| Indication | Dose | Purpose |
|---|---|---|
| Palliation (pain) | 8 Gy single fraction | Quick pain relief |
| Post-operative | 30 Gy in 10 fractions | Local control |
| Spinal cord compression | 20-30 Gy | Decompression if non-surgical |
| Impending fracture (low Mirels) | 30 Gy | Prevent fracture |
Most bone metastases are radiosensitive except renal cell and melanoma.
Q: "How do you differentiate a pathological fracture from a traumatic fracture in the elderly?"
| Feature | Pathological | Traumatic |
|---|---|---|
| Mechanism | Minimal trauma | Significant trauma |
| Prodromal pain | Common (weeks) | Absent |
| X-ray | Lytic lesion, cortical destruction | Normal bone prior to fracture |
| Constitutional symptoms | Weight loss, fatigue | Absent |
| Risk factors | Malignancy history, smoking | Falls risk, osteoporosis |
Any fracture with minimal trauma or visible lesion on X-ray should be considered pathological until proven otherwise.