Biopsy in orthopaedic oncology — a patient guide to tissue diagnosis

Biopsy is the final and most critical step in diagnosing bone and soft-tissue tumours — it is almost never the first test. Most tumours need tissue confirmation, but some clearly benign lesions may not:

• Osteoid osteoma with characteristic imaging
• Typical osteochondroma in young patients
• Simple bone (unicameral) cysts
• Non-ossifying fibroma in children
• Subcutaneous lipomas under 5 cm

Key point: Whether the lesion looks benign or malignant, your biopsy should always be performed by an orthopaedic oncologist at a specialised centre.

Studies show improper biopsy placement or technique can have devastating consequences:

• Amputation required specifically due to biopsy errors in up to 18% of patients3
• Higher complication rates at non-specialised centres
• Diagnostic accuracy decreases significantly outside expert centres

Evidence from the American Musculoskeletal Tumor Society shows inappropriate biopsy significantly increases the chance of more radical treatment than originally expected.6

Key point: The surgeon performing your biopsy should be the same specialist who will perform your definitive treatment.

• Blood tests: complete blood count, clotting studies, liver and kidney function.
• Imaging review: all X-rays, CT, MRI and PET scans must be complete before biopsy.
• Informed consent: a detailed discussion in your preferred language about risks and benefits.
• Medication review: stop blood-thinning medications as directed.

Key point: Biopsy should never be performed until imaging is complete — this helps determine the safest approach and most representative area to sample.

Your biopsy targets the most representative area:

• Periphery of the tumour — the growing edge contains the most active cells.
• Solid areas — avoiding necrotic or haemorrhagic centres.
• Extraosseous component — if a bone tumour extends into soft tissue, this area is equally representative and safer than drilling through bone.

For soft-tissue tumours, multiple samples from different areas ensure accurate diagnosis since these tumours can be heterogeneous.

Frozen section provides immediate microscopic analysis during surgery to confirm adequate tumour tissue, guide surgical decisions and differentiate benign from malignant in ambiguous cases.

• Overall diagnostic accuracy: 86–93% 4
• Accurate diagnosis in 54% of cases; helpful for surgical decisions in 75% 7
• Osteoclastic giant cell tumours: 97–98%
• Osteogenic tumours: 90–96%
• Chondrogenic tumours: 84–93% 10

Key point: Final treatment should be based on permanent-section diagnosis, not frozen section alone.

Immunohistochemistry (IHC): protein stains that help identify tumour type — e.g. CD99 for Ewing sarcoma, MDM2 for liposarcoma. May add 3–4 days to diagnosis.

Molecular testing:

• FISH — detects specific gene fusions
• RT-PCR — identifies fusion genes like EWS-FLI1 in Ewing sarcoma
• Next-Generation Sequencing — comprehensive genetic analysis

Modern sarcoma diagnosis increasingly relies on molecular testing — over 80 distinct sarcoma types exist, many defined by specific genetic alterations.58

Key point: Adequate tissue must be obtained for both routine diagnosis and molecular testing — this is why proper biopsy technique is crucial.

Core needle biopsy is performed under local anaesthesia — discomfort similar to a blood draw from a large vein, oral pain medication for 2–3 days, usually done as an outpatient.

Open biopsy is performed under general or regional anaesthesia — IV pain medication initially, oral pain medication for 5–7 days, may require a 1–2 day hospital stay.

Key point: Modern pain management makes biopsy procedures well-tolerated with minimal discomfort.

• Routine diagnosis: 3–4 days
• With immunohistochemistry: 5–7 days
• With molecular testing (FISH, PCR): 7–14 days
• Complex cases requiring consultation: up to 3 weeks

Complications are rare when performed at specialised centres:

• Infection: <1% with proper sterile technique
• Bleeding or haematoma: minimised with careful technique
• Pathological fracture: <0.5% with the right approach
• Nerve or vessel injury: rare with image guidance
• Tumour seeding: theoretical, extremely rare with proper technique

Complication rates are significantly lower at high-volume sarcoma centres compared with general hospitals.1

• Initial sample was inadequate (necrosis, processing issues)
• Diagnosis doesn't match clinical and imaging findings
• Additional tissue needed for molecular testing
• Previous biopsy performed elsewhere with questionable technique

• Multidisciplinary tumour-board review
• Second opinion from a sarcoma pathology expert
• Possible repeat biopsy if sampling error suspected
• Additional molecular testing if appropriate