# CIM Case: Metastatic Hepatocellular Carcinoma to Proximal Tibia ## Clinical Scenario **Patient:** 62-year-old man **Presentation:** Progressive right knee pain for 6 weeks, now unable to weight-bear, mechanical symptoms with giving way **Relevant history:** Hepatocellular carcinoma diagnosed 18 months ago (Child-Pugh A cirrhosis, Hepatitis B), underwent transarterial chemoembolisation (TACE), current AFP mildly elevated, 10kg weight loss over 3 months, no known metastases on previous staging **Examination findings:** - Weight 65kg (previously 75kg) - Antalgic gait, uses walking stick - Tender over anteromedial proximal tibia - Firm, fixed mass palpable - Range of motion limited by pain (5-90°) - Stable to varus/valgus stress - Neurovascularly intact distally - Mild hepatomegaly on abdominal examination - No jaundice --- ## Investigations Provided ### Laboratory Results | Test | Result | Normal Range | Interpretation | |------|--------|--------------|----------------| | AFP | 185 ng/mL | <10 ng/mL | ↑ Elevated (HCC marker) | | Hb | 105 g/L | 130-170 g/L | ↓ Anaemia | | WCC | 7.2 ×10⁹/L | 4-11 ×10⁹/L | Normal | | Platelets | 95 ×10⁹/L | 150-400 ×10⁹/L | ↓ Thrombocytopaenia (cirrhosis) | | INR | 1.4 | 0.9-1.1 | ↑ Mildly elevated (liver dysfunction) | | Albumin | 32 g/L | 35-50 g/L | ↓ Hypoalbuminaemia | | Bilirubin | 22 μmol/L | <20 μmol/L | ↑ Mildly elevated | | ALP | 245 U/L | 30-120 U/L | ↑ Elevated (bone/liver) | | Calcium | 2.5 mmol/L | 2.2-2.6 mmol/L | Normal | | Creatinine | 92 μmol/L | 60-110 μmol/L | Normal | ### Imaging **Image 1: AP and Lateral Radiographs of Right Knee** **Radiological features:** - Large lytic lesion in proximal tibial metaphysis - Cortical erosion and destruction of anteromedial cortex - No matrix calcification (not osteoid or chondroid) - Pathological fracture risk (cortical involvement >50%) - No periosteal reaction - Aggressive permeative pattern **Image 2: MRI Right Knee with Contrast** **MRI findings:** - 5 × 4 × 6 cm mass in proximal tibial metaphysis - Low T1, high T2 signal with heterogeneous enhancement - Marked hypervascularity (typical of HCC metastases) - Cortical breakthrough with small soft tissue component - No joint involvement - Popliteal vessels displaced but not encased **Image 3: CT Chest/Abdomen/Pelvis (Staging)** **Findings:** - HCC in right lobe of liver (known, stable) - Multiple small pulmonary nodules (new - likely metastases) - No other skeletal lesions visible - No visceral metastases apart from lung --- ## Questions & Model Answers **Differential Diagnosis:** | Diagnosis | Supporting Features | Against | |-----------|---------------------|---------| | **Metastatic HCC** | Known HCC, lytic lesion, elevated AFP, hypervascular on MRI | - | | Other metastasis | Age, lytic lesion, weight loss | Known primary is HCC | | Primary bone tumour (chondrosarcoma) | Lytic proximal tibia lesion | Age, known HCC, AFP elevated | | Plasmacytoma/myeloma | Lytic lesion | Known HCC, AFP elevated | | Giant cell tumour | Proximal tibia location | Age >40, known malignancy, AFP | **Most Likely Diagnosis: Metastatic hepatocellular carcinoma to proximal tibia** **Key Supporting Features:** - Known HCC with mildly elevated AFP - Lytic, hypervascular lesion (characteristic of HCC metastases) - Weight loss and constitutional symptoms - New pulmonary metastases on staging **Important Principle:** In patients over 40 with a lytic bone lesion and known malignancy, metastasis is the most likely diagnosis until proven otherwise. > **Consultant Tip:** Metastasis is more common than primary bone tumour in adults. Always search for a known or occult primary. **Biopsy Considerations:** **Arguments FOR Biopsy:** - Histological confirmation before major surgery - Could be different primary (rare second malignancy) - Treatment planning depends on tissue diagnosis **Arguments AGAINST Biopsy:** - Known HCC with characteristic imaging - Risk of bleeding (HCC metastases are highly vascular) - Thrombocytopaenia and coagulopathy - May seed biopsy tract **Recommendation:** In this case with known HCC, characteristic hypervascular imaging, and elevated AFP, biopsy may not be necessary if MDT agrees on diagnosis. However, if any doubt, CT-guided core biopsy can be performed with: - Coagulation optimisation (vitamin K, FFP, platelet transfusion) - Interventional radiology involvement - Plan for embolisation if bleeding - Avoid biopsy tract through planned surgical field **HCC Metastasis Bleeding Risk:** - HCC metastases are HIGHLY VASCULAR - Significant haemorrhage risk with biopsy or surgery - May require preoperative embolisation > **Consultant Tip:** HCC metastases are vascular. Consider preoperative embolisation before biopsy or surgery to reduce bleeding risk. **Mirels Scoring System for Pathological Fracture:** | Variable | Score 1 | Score 2 | Score 3 | |----------|---------|---------|---------| | **Site** | Upper limb | Lower limb | Peritrochanteric | | **Pain** | Mild | Moderate | Functional (weight-bearing) | | **Lesion type** | Blastic | Mixed | Lytic | | **Size (cortical destruction)** | <1/3 | 1/3-2/3 | >2/3 | **Interpretation:** - Score ≤7: Low risk (≈5%) - radiotherapy alone - Score 8: Intermediate (15%) - consider prophylactic fixation - Score ≥9: High risk (≈33%) - prophylactic fixation recommended **This Patient's Score:** - Site: Lower limb = 2 - Pain: Functional (giving way with weight-bearing) = 3 - Lesion type: Lytic = 3 - Size: >2/3 cortical destruction = 3 - **Total: 11 - HIGH RISK** **Recommendation:** Prophylactic stabilisation is indicated to prevent pathological fracture. > **Consultant Tip:** Mirels score ≥9 = prophylactic fixation. Lower limb, lytic, functional pain, large lesions all score highly. **Treatment Goals Assessment:** **Prognosis Estimation:** - Metastatic HCC: median survival 6-12 months - Lung metastases present: worse prognosis - Child-Pugh A: relatively preserved liver function - ECOG performance status: currently mobile with aids **Treatment Intent:** - This is PALLIATIVE, not curative - Goals: pain relief, prevent fracture, maintain mobility, quality of life **Surgical Options:** | Option | Indication | Considerations | |--------|------------|----------------| | **Endoprosthetic reconstruction** | Large destructive lesion, poor bone stock | Best for rapid rehabilitation, high functional demands | | **Curettage + cement + plate** | Contained lesion, adequate bone stock | Less morbidity, faster surgery | | **Above-knee amputation** | Massive destruction, uncontrollable bleeding, infection | Rarely needed for metastatic disease | | **Radiotherapy alone** | Non-operative candidates, very short prognosis | Does not prevent fracture | **For This Patient:** Given large lesion with >2/3 cortical destruction, proximal tibial reconstruction options: 1. **Curettage + cement + medial buttress plate** - if contained 2. **Proximal tibial endoprosthesis** - if extensive destruction/fracture **Preoperative Considerations:** - Preoperative embolisation (reduce bleeding) - Correct coagulopathy (vitamin K, FFP) - Platelet transfusion (target >100) - Blood products available (cross-match 4 units) - Medical oncology input for systemic therapy timing > **Consultant Tip:** Treatment is palliative. Balance morbidity of surgery against expected survival. Aim for single procedure that allows rapid return to function. **Surgical Technique:** **Preoperative:** - Preoperative angiography + embolisation (reduces bleeding 50-70%) - Correct coagulopathy - Cell saver available - Type and cross-match 4 units **Approach:** - Anteromedial approach to proximal tibia - Create cortical window over lesion - Size window appropriately (needs to span defect) **Curettage:** - Thorough mechanical curettage - Remove all gross tumour - Use high-speed burr to extend margins - Identify and protect neurovascular structures **Local Adjuvants (Extend Margins):** | Adjuvant | Mechanism | Depth of Effect | |----------|-----------|-----------------| | High-speed burr | Mechanical/thermal | 1-2 mm | | Phenol | Chemical cauterisation | 1 mm | | Argon beam coagulator | Thermal ablation | 1-2 mm | | Liquid nitrogen | Cryotherapy | Variable | | H₂O₂ (hydrogen peroxide) | Oxidative damage | Minimal | **Reconstruction:** - Pack cavity with PMMA cement (polymethyl methacrylate) - Cement provides immediate stability and local tumour control - Span defect with plate if cortical destruction >50% - Consider prophylactic IM nail for diaphyseal extension **Postoperative:** - Weight-bearing as tolerated (cement gives immediate stability) - Adjuvant radiotherapy (30 Gy in 10 fractions) - improves local control - VTE prophylaxis - Pain management > **Consultant Tip:** Cement provides immediate weight-bearing. Combine with plate if significant cortical loss. Consider adjuvant radiotherapy for metastatic lesions. **Preoperative Embolisation:** **Indications:** - Hypervascular metastases (renal cell, HCC, thyroid) - Reduces intraoperative blood loss 50-70% - Allows safer surgical resection **Tumours Requiring Consideration:** - **Renal cell carcinoma** - most vascular - **Hepatocellular carcinoma** - highly vascular - **Thyroid carcinoma** - vascular - (Less vascular: breast, prostate, lung) **Technique:** - Performed by interventional radiology - Angiography to identify feeding vessels - Selective embolisation with particles/coils - Ideally 24-48 hours before surgery **Risks:** - Post-embolisation syndrome (pain, fever, swelling) - Skin necrosis - Nerve injury (if collateral supply affected) - Incomplete embolisation - Tumour lysis syndrome (rare) **For This Patient:** HCC metastases are highly vascular. Preoperative embolisation strongly recommended to reduce intraoperative bleeding, especially given existing coagulopathy. > **Consultant Tip:** Renal and hepatocellular carcinoma metastases are highly vascular. Preoperative embolisation significantly reduces operative bleeding. --- ## Key Teaching Points ### Pattern Recognition **This pattern suggests Metastatic Bone Disease:** - Adult >40 years with lytic bone lesion - Known primary malignancy (HCC) - Weight loss and constitutional symptoms - Multiple organ involvement (liver + lung + bone) **Lytic Bone Metastases - Common Primaries (Mnemonic: "Kidney, Thyroid, Lung - They Lick Bone"):** - **K**idney (renal cell) - **T**hyroid - **L**ung - **B**reast (can be mixed/blastic) **HCC Metastasis Characteristics:** - Highly vascular (like renal cell) - Usually lytic - Often solitary skeletal metastasis - AFP may be elevated - Risk of significant bleeding ### Critical Management Points 1. **MDT discussion essential** - oncology, palliative care, hepatology 2. **Define treatment intent** - palliative vs curative 3. **Mirels score for fracture risk** - ≥9 requires prophylactic fixation 4. **Preoperative embolisation** - for vascular tumours (HCC, RCC, thyroid) 5. **Correct coagulopathy** - cirrhosis causes INR elevation, thrombocytopaenia 6. **Single procedure** - aim for one surgery that allows immediate mobilisation --- ## Common Examiner Follow-ups **Q: "How do you differentiate a solitary bone metastasis from a primary bone tumour?"** | Feature | Metastasis | Primary Bone Tumour | |---------|------------|---------------------| | Age | Usually >40 | Bimodal (adolescent/elderly) | | History | Known primary, weight loss | Usually no prior malignancy | | Lesion location | Often appendicular metaphysis | Varies by tumour type | | Multiple lesions | Common | Rare (except myeloma) | | Staging scan | Other metastases often found | Usually solitary | | Histology | Matches primary | Distinct histology | **Key:** In adults over 40, assume metastasis until proven otherwise. --- **Q: "What is your approach to bone metastasis from unknown primary?"** Workup for occult primary: 1. **History and examination** - especially breast, prostate, thyroid, skin 2. **Basic bloods** - PSA (men), AFP, LDH, calcium 3. **Staging CT** - chest/abdomen/pelvis 4. **Bone scan or PET-CT** - extent of skeletal disease 5. **Mammogram** (women) 6. **CT-guided biopsy** with immunohistochemistry **Common occult primaries:** Lung (30%), kidney (10%), unknown (10%) --- **Q: "When would you consider amputation for metastatic bone disease?"** Amputation rarely indicated for metastatic disease. Consider when: - Pathological fracture with neurovascular injury - Massive uncontrollable haemorrhage - Fungating/infected tumour - Failed reconstruction with persistent sepsis - Selected cases with solitary metastasis and curative intent (rare) For most patients, limb-preserving palliative surgery is preferred. --- ## Related Topics - Pathological Fractures - Mirels Scoring System - Endoprosthetic Reconstruction - Preoperative Embolisation - Palliative Care in Orthopaedics