BIOPSY PRINCIPLES IN ORTHOPAEDIC ONCOLOGY
Mankin Principles | Approach Planning | Avoid Contamination | Tumor Center Collaboration
BIOPSY TYPES
Critical Must-Knows
- All biopsies should be performed by the surgeon who will do the definitive resection or in consultation with tumor center
- Longitudinal incisions only - transverse incisions contaminate multiple compartments and may preclude limb salvage
- Biopsy tract must be in the planned resection field - entire tract including skin incision will be excised
- Minimize hematoma - use meticulous hemostasis, minimal tourniquet time, compression dressing, avoid drains if possible
- Never perform excisional biopsy for suspected sarcoma - violates oncologic principles and contaminates surrounding tissue
Examiner's Pearls
- "Mankin's series showed 18.2% major biopsy errors leading to altered treatment in 8.5% and unnecessary amputation in 4.5%
- "The three cardinal sins: wrong biopsy type, wrong approach, inadequate specimen handling
- "Image-guided core needle biopsy has 90% diagnostic accuracy with minimal complications
- "Always discuss suspected bone or soft tissue tumor with tumor center BEFORE biopsy
Clinical Imaging
Imaging Gallery
Critical Biopsy Principles - Avoid Mankin Errors
Mankin's Biopsy Errors
18.2% major errors in referral biopsies led to altered treatment (8.5%) and unnecessary amputations (4.5%). Key errors: wrong biopsy type (30%), inappropriate approach contaminating compartments (28%), poor hemostasis causing hematoma (25%), inadequate tissue (17%).
The Longitudinal Rule
NEVER use transverse incisions. Longitudinal incisions parallel to neurovascular bundle allow excision of entire tract en bloc. Transverse incisions contaminate multiple compartments, destroy tissue planes, and may necessitate amputation.
Resection Field Principle
Every biopsy tract must be in the planned resection field. The entire tract including skin incision will be excised en bloc with tumor. Poorly planned biopsy can convert limb salvage to amputation.
Tumor Center Collaboration
Discuss all suspected sarcomas with tumor center BEFORE biopsy. Many biopsies should be performed at the treating center by the definitive surgeon. Inappropriate biopsy is the most common referral error.
At a Glance
Biopsy technique in orthopaedic oncology is critical—Mankin's series showed 18.2% major errors in referral biopsies leading to altered treatment in 8.5% and unnecessary amputation in 4.5%. Cardinal principles: all biopsies should be performed by the definitive resection surgeon or in consultation with a tumor center; use longitudinal incisions only (transverse incisions contaminate multiple compartments); the biopsy tract must be in the planned resection field (will be excised en bloc); and minimize hematoma with meticulous hemostasis. Core needle biopsy (11-14 gauge) is first-line with 90% diagnostic accuracy. Never perform excisional biopsy for suspected sarcoma—this violates oncologic principles. Discuss all suspected bone/soft tissue tumors with a tumor center BEFORE biopsy.
MANKINMankin Biopsy Principles
Memory Hook:MANKIN's principles prevent the catastrophic errors that led to his landmark 1982 study on biopsy complications
RESECTBiopsy Approach Planning
Memory Hook:RESECT reminds you that the biopsy tract will be RESECTed with the tumor - plan accordingly!
FRESHSpecimen Handling
Memory Hook:Send FRESH tissue - proper specimen handling is essential for accurate diagnosis
BIOPSYIndications for Biopsy
Memory Hook:When do you need a BIOPSY? These indications guide decision-making
Overview and Epidemiology
Biopsy is the definitive diagnostic procedure for suspected bone and soft tissue tumors. The technique and timing of biopsy are critical - improper biopsy can compromise subsequent treatment, increase morbidity, and even necessitate amputation in cases where limb salvage would otherwise be possible.
Mankin's Landmark Study
Mankin's 1982 study of 329 patients referred to a sarcoma center after biopsy elsewhere revealed that 18.2% had major biopsy errors. These errors led to altered treatment in 8.5% of patients and unnecessary amputation in 4.5%. The most common errors were: wrong biopsy type (30%), inappropriate approach (28%), poor hemostasis causing hematoma (25%), and inadequate tissue (17%). This study established the principle that biopsies should be performed by or in consultation with the surgeon who will perform the definitive resection.
Fundamental Principles
The core principles of tumor biopsy were established by Mankin and remain unchanged:
Pre-Biopsy Planning
- Complete imaging workup first: Plain films, MRI, CT chest
- Multidisciplinary review: Radiology, pathology, oncology
- Tumor center consultation: Discuss plan before biopsy
- Definitive surgeon involvement: Ideally performs biopsy
- Image review: Understand anatomy, plan approach
Technical Execution
- Appropriate biopsy type: Core needle for most lesions
- Longitudinal approach: Parallel to neurovascular structures
- Single compartment: Do not violate multiple planes
- Resection field: Entire tract must be excisable
- Meticulous hemostasis: Minimize hematoma formation
The Golden Rule of Tumor Biopsy
If you are not going to perform the definitive resection, do not perform the biopsy. Contact a tumor center first. An inappropriately placed biopsy can convert a limb salvage procedure to an amputation, increase surgical morbidity, or compromise oncologic outcome.
Oncologic Rationale
The biopsy tract becomes contaminated with tumor cells and must be excised en bloc with the tumor during definitive resection. Poor biopsy technique can:
- Seed tumor cells into surrounding tissue via hematoma
- Violate tissue planes making resection margins unclear
- Contaminate multiple compartments necessitating wider resection
- Compromise neurovascular structures precluding limb salvage
- Create skin bridges between biopsy and tumor requiring skin grafting
Pathophysiology and Rationale
When Biopsy is Indicated
Not all bone and soft tissue lesions require biopsy. Many benign lesions can be diagnosed with certainty on imaging and clinical grounds.
Biopsy Decision-Making
| Clinical Scenario | Biopsy Needed? | Rationale |
|---|---|---|
| Classic osteochondroma in adolescent | No | Pathognomonic imaging, age-appropriate, asymptomatic |
| Unicameral bone cyst in proximal humerus, child | No (unless atypical) | Classic imaging and location, can treat empirically |
| Enchondroma hand phalanx, incidental | No | Classic appearance, no aggressive features |
| Soft tissue mass greater than 5cm or deep | Yes | High risk of malignancy, requires tissue diagnosis |
| Bone lesion with aggressive features | Yes | Permeative pattern, cortical destruction, soft tissue mass |
| Pathological fracture through lesion | Yes (after stabilization) | Need diagnosis to guide adjuvant treatment |
| Metastatic disease suspected (known primary) | Maybe | Biopsy if changes treatment or confirms diagnosis |
The 5cm Rule for Soft Tissue Masses
Any soft tissue mass that is deep to fascia, larger than 5cm, or growing on serial imaging should be considered malignant until proven otherwise and requires biopsy. Superficial subcutaneous lipomas less than 5cm can usually be observed or excised without pre-operative biopsy. However, atypical features (firmness, fixation, rapid growth) mandate biopsy regardless of size.
Absolute Indications
Lesions Requiring Biopsy
- Aggressive imaging features (permeative, moth-eaten destruction)
- Age-inappropriate lesion (e.g., lytic femur lesion age 40)
- Soft tissue mass associated with bone lesion
- Pathological fracture through unknown lesion
- Rapid growth or symptom progression
- Atypical features not fitting benign diagnosis
- Any deep mass (below investing fascia)
- Superficial mass greater than 5cm
- Rapid growth on serial imaging
- Firm, fixed, or irregular mass
- Recurrent mass after prior excision
- Symptomatic (pain, paresthesia)
- Metastatic workup (establish diagnosis)
- Pre-operative planning (neoadjuvant therapy)
- Monitor treatment response (re-biopsy)
- Uncertain imaging despite full workup
- Infection vs tumor differential
Contraindications to Biopsy
Biopsy should be deferred or avoided in specific situations:
- Classic benign imaging: Pathognomonic appearance (e.g., fibrous cortical defect)
- Vascular lesions: Risk of hemorrhage (consider embolization first)
- Inadequate imaging: Complete MRI and staging studies first
- Infection suspected: Aspiration for culture, not biopsy
- Coagulopathy uncorrected: Bleeding risk too high
- Patient unfit for treatment: Diagnosis will not change management
Classification
Classification of Biopsy Types
Biopsy Type Classification
| Biopsy Type | Technique | Tissue Yield | Primary Indication |
|---|---|---|---|
| Fine Needle Aspiration (FNA) | 22-25 gauge needle, multiple passes | Cells only (cytology) | Confirmatory role, metastatic disease |
| Core Needle Biopsy | 11-16 gauge, image-guided | Tissue cores (histology) | First-line for most lesions |
| Incisional Biopsy | Open surgical, partial removal | Tissue block (1-2cm cube) | When needle inadequate |
| Excisional Biopsy | Complete lesion removal | Entire lesion with margin | Only small superficial lesions under 3cm |
Needle Gauge Selection
Soft tissue lesions:
- 14-16 gauge needles adequate
- Ultrasound guidance preferred
Bone lesions:
- 11-13 gauge for harder cortex
- CT guidance for accuracy
Core Number Requirements
Minimum cores required:
- 3-5 cores for soft tissue
- 4-6 cores for bone lesions
Rationale:
- Accounts for heterogeneous tumors
- Allows immunohistochemistry
- Provides tissue for molecular studies
Clinical Presentation and Indications
Fine Needle Aspiration (FNA)
Technique
- Needle: 22-25 gauge
- Yield: Cells for cytology only
- Guidance: Palpation or image-guided
- Passes: Multiple (4-6 typical)
- Processing: Air-dried smears, alcohol-fixed
Role in Orthopaedics
- Primary diagnosis: Generally insufficient
- Confirmatory role: Metastasis with known primary
- Limitations: No architecture, limited immunohistochemistry
- Accuracy: 60-80% sensitivity for sarcoma
- Inadequate rate: 10-20%
Advantages:
- Minimally invasive, office-based
- Multiple sites can be sampled
- Minimal contamination risk
- Quick turnaround for cytology
Disadvantages:
- Cannot assess architecture (critical for bone tumors)
- Limited tissue for immunohistochemistry and molecular studies
- High inadequate specimen rate
- Reader-dependent (requires expert cytopathologist)
FNA Role in Musculoskeletal Oncology
FNA has a limited role in primary diagnosis of bone and soft tissue sarcomas because architectural assessment is essential for grading and subtyping. FNA is useful for: (1) confirming metastatic disease when primary cancer is known, (2) diagnosing lymphoma when combined with flow cytometry, and (3) initial triage in resource-limited settings. Core needle biopsy is superior for primary sarcoma diagnosis.
Core Needle Biopsy (CNB)
Core needle biopsy is the first-line biopsy technique for most suspected bone and soft tissue tumors.
Core Needle Biopsy Technical Details
| Parameter | Soft Tissue | Bone Lesion |
|---|---|---|
| Needle gauge | 14-16 gauge | 11-13 gauge (larger for bone) |
| Guidance | Ultrasound or CT | CT preferred (bone cortex visualization) |
| Number of cores | 3-5 cores minimum | 4-6 cores (bone harder to sample) |
| Anesthesia | Local infiltration | Local plus conscious sedation often |
| Approach planning | Longitudinal trajectory | Through planned resection field |
Advantages:
- High diagnostic accuracy: 85-95% for sarcoma
- Tissue architecture preserved: Allows histologic grading
- Sufficient for immunohistochemistry: Multiple cores provide tissue
- Minimal contamination: Small needle tract, easily excised
- Image-guided: Targets viable tumor, avoids necrosis
- Outpatient procedure: Lower morbidity than open biopsy
Disadvantages:
- Sampling error (small tissue volume)
- May be inadequate for heterogeneous tumors
- Requires expert musculoskeletal pathologist
- Cannot perform frozen section reliably
- May need repeat if non-diagnostic
Image Guidance for Core Biopsy
CT guidance is preferred for bone lesions (visualizes cortex, guides through planned resection field). Ultrasound guidance is preferred for soft tissue masses (real-time visualization, no radiation, can avoid vessels). The radiologist performing the biopsy should communicate with the surgeon regarding planned approach and resection field.
Multiple Cores Essential
A single core is insufficient for sarcoma diagnosis. Minimum 3-5 cores should be obtained to: (1) ensure representative sampling, (2) provide tissue for permanent sections, (3) allow immunohistochemistry if needed, (4) send fresh tissue for culture or molecular studies. Inadequate sampling is a common cause of non-diagnostic biopsy.
Incisional Biopsy
Open incisional biopsy involves a limited surgical incision to obtain a tissue sample without removing the entire lesion.
Indications for incisional over needle biopsy:
- Prior needle biopsy non-diagnostic (inadequate or inconclusive)
- Heterogeneous tumor: Large areas of necrosis, need larger sample
- Bone lesion requiring instrumentation: Hard cortex preventing needle access
- Surgeon preference: When definitive surgeon prefers to perform biopsy
- Suspected lymphoma: Need tissue architecture and fresh tissue for flow
Incisional Biopsy Technique
- Review all imaging with treating surgeon
- Mark incision site with patient awake (anatomic landmarks)
- Plan longitudinal incision in resection field
- Ensure entire tract can be excised en bloc
- Prepare for frozen section (confirm adequate tissue)
- Longitudinal skin incision, minimal length
- Dissect directly to lesion (do not create flaps)
- Single compartment approach
- Remove tissue block (1-2cm cube minimum)
- Sample viable tumor (periphery), avoid necrotic center
- Send fresh tissue for culture in sterile container
- Meticulous hemostasis (bipolar, bone wax)
- Irrigate wound thoroughly
- Layered closure (no dead space)
- Avoid drain if possible (if needed, exit through incision)
- Compression dressing for 48 hours
The Drain Dilemma
Drains should be avoided if at all possible in tumor biopsies. Drains create a tract that can disseminate tumor cells and must be excised en bloc with the tumor. If a drain is absolutely necessary (e.g., large cavity in bone after biopsy), it must exit through the biopsy incision (not a separate stab incision) so the entire tract can be resected.
Excisional Biopsy
Excisional biopsy involves removing the entire lesion with a margin of normal tissue.
Appropriate scenarios (VERY LIMITED):
- Small superficial lesion (less than 3cm) with low suspicion for sarcoma
- Subcutaneous lipoma typical appearance, mobile, soft
- Pedunculated lesion (e.g., presumed skin tag, neurofibroma)
- Patient preference for complete removal if benign likely
CONTRAINDICATIONS (Do NOT perform excisional biopsy):
- Deep mass (below fascia) - unacceptable contamination risk
- Large mass (greater than 5cm) - violates oncologic principles
- Firm or fixed mass - suggests malignancy
- Imaging features of sarcoma - inappropriate marginal excision
- Bone lesion with aggressive features - requires staging and planning
The Excisional Biopsy Error
Excisional biopsy of a suspected sarcoma is a major error. It results in: (1) tumor spillage into surrounding tissue, (2) loss of anatomic planes for definitive resection, (3) contamination of adjacent compartments, (4) need for much wider re-excision, and (5) potential conversion of limb salvage to amputation. This error accounted for 30% of major complications in Mankin's series.
Investigations and Imaging Guidance
The Longitudinal Incision Rule
The single most important principle in biopsy technique is the longitudinal incision.
Longitudinal vs Transverse Incisions
| Feature | Longitudinal (Correct) | Transverse (WRONG) |
|---|---|---|
| Direction | Parallel to neurovascular bundle and long axis of limb | Perpendicular to long axis, crosses compartments |
| Extensibility | Can extend proximally/distally for definitive resection | Cannot be extended without creating skin flaps |
| Compartments violated | Single compartment | Multiple compartments contaminated |
| Resection implications | Entire tract excised en bloc with tumor | May necessitate amputation or massive skin grafting |
| Hematoma tracking | Confined to single compartment | Spreads across multiple compartments |
Transverse Incisions are Never Acceptable
A transverse biopsy incision can convert a limb salvage to an amputation. Transverse incisions cross multiple tissue planes and compartments. During definitive resection, the entire contaminated area (including all crossed compartments) must be excised. This may require sacrifice of critical neurovascular structures or amputation. Examiners will fail candidates who suggest transverse biopsy incisions.
Anatomic Approach Principles
Upper Limb Approaches
Shoulder/Proximal Humerus:
- Deltopectoral approach (anterior access)
- Posterior approach through deltoid (posterior tumors)
Arm/Forearm:
- Longitudinal over tumor in line with definitive incision
- Avoid crossing antecubital fossa
Hand:
- Longitudinal dorsal or volar
- Midaxial for digit lesions
Lower Limb Approaches
Thigh:
- Anterolateral (vastus lateralis interval)
- Medial (direct to adductors)
- Posterior (through hamstrings)
Leg:
- Anteromedial (medial to tibial crest)
- Posterolateral (between peronei and gastrocnemius)
Foot:
- Dorsal longitudinal most common
Specific Technical Considerations
Soft Tissue Mass Biopsy Technique
Pre-operative:
- Review MRI in axial cuts (identify safest trajectory)
- Mark skin incision with patient awake (muscle relaxation changes anatomy)
- Identify neurovascular structures to avoid
- Plan incision to be within resection field
Incision placement:
- Directly over mass (shortest distance to tumor)
- Longitudinal orientation
- Avoid neurovascular bundles (approach between muscles)
- Consider extensile approach for definitive surgery
Tissue dissection:
- Do NOT raise skin flaps (increases contamination)
- Dissect between muscles to reach mass
- Stay in single compartment
- Avoid opening neurovascular sheath
Specimen acquisition:
- Sample periphery of mass (avoid necrotic center)
- Minimum 1cm cube of tissue
- Send fresh specimen for culture (rule out infection)
- Obtain hemostasis before closing
Closure:
- Layered closure (no dead space)
- No drain (or drain through incision if essential)
- Compression dressing
This approach ensures minimal contamination and preserves limb salvage options.
Management - Biopsy Technique
Communication with Pathologist
Essential information for pathologist:
- Patient age and relevant history
- Location and size of lesion (anatomic compartment)
- Imaging findings and differential diagnosis
- Clinical question (primary tumor? metastasis? infection?)
- Fresh tissue sent separately for culture
- Request for frozen section if applicable
The Pathologist is Your Partner
Call the pathologist before the biopsy to discuss the case. Provide imaging and clinical context. This allows the pathologist to: (1) prepare appropriate fixatives and stains, (2) plan for ancillary studies (immunohistochemistry, molecular), (3) have frozen section capability if needed, (4) optimize specimen handling. Poor communication with pathology is a common cause of non-diagnostic biopsies.
Specimen Processing
From Biopsy to Diagnosis
- Send portion in sterile container (not formalin) for culture
- Touch prep cytology can be done on fresh tissue
- Frozen section if requested (limited role in sarcoma)
- Photograph specimen if desired
- Minimize time to pathology (tissue degradation)
- Majority of tissue in 10% formalin for permanent sections
- Fixation time 24-48 hours before processing
- Decalcification if bone (EDTA preferred over acid)
- Embedding in paraffin blocks
- Sectioning at 4-5 microns thickness
- H&E staining: Standard hematoxylin and eosin
- Immunohistochemistry: Panel based on differential
- Special stains: As needed (trichrome, reticulin)
- Molecular studies: FISH, PCR, NGS if indicated
- Expert musculoskeletal pathologist review
- Diagnosis with grading if malignant
- Immunohistochemistry results
- Molecular findings if performed
- Comment on adequacy and differential
- Recommendations for further testing if needed
Frozen Section Limitations
Frozen section has LIMITED ROLE in sarcoma biopsy:
- Cannot reliably diagnose sarcoma subtype (architecture disrupted by freezing)
- Cannot grade sarcoma (cellular detail lost)
- Risk of using up tissue (small biopsies may be exhausted)
- Delaying definitive diagnosis (frozen is preliminary only)
Appropriate uses of frozen section:
- Confirm adequate tissue obtained (vs adipose, muscle, necrosis)
- Rule out infection (gram stain on frozen)
- Confirm diagnostic material in difficult-to-access lesions (spine, pelvis)
- Triage tissue for ancillary studies (flow cytometry for lymphoma)
Frozen Section Cannot Diagnose Sarcoma
Do NOT rely on frozen section for definitive sarcoma diagnosis or grading. The architectural details and cellular morphology required for sarcoma diagnosis are lost in frozen sections. Frozen section should only confirm that diagnostic tissue has been obtained, not provide the final diagnosis. Permanent sections with immunohistochemistry are essential.
Ancillary Studies
Modern sarcoma diagnosis often requires studies beyond standard H&E microscopy:
Ancillary Diagnostic Studies
| Study Type | Indications | Examples |
|---|---|---|
| Immunohistochemistry | Subtype sarcoma, confirm diagnosis | Desmin (muscle), S100 (nerve), CD34 (vascular), keratin (epithelial) |
| Molecular/Cytogenetics | Diagnostic translocations | EWSR1 (Ewing), SYT-SSX (synovial), MDM2 (liposarcoma) |
| Flow Cytometry | Lymphoma diagnosis | B-cell vs T-cell markers, clonality assessment |
| Culture | Rule out infection | Bacterial, fungal, mycobacterial cultures from fresh tissue |
| Electron Microscopy | Poorly differentiated tumors | Rare, for ultrastructural features (seldom needed now) |
Surgical Technique
Core Needle Biopsy Technique
Step-by-Step Core Needle Biopsy
- Review all imaging with radiologist
- Plan trajectory through resection field
- Mark skin entry point
- Confirm pathology availability
- Obtain informed consent
- Position for optimal access (prone/supine/lateral)
- Ensure patient comfort (sedation if needed)
- Sterile prep and drape
- Local anesthesia to skin and tract
- Small skin nick with scalpel
- Insert coaxial guiding cannula
- Advance under image guidance
- Confirm position within lesion
- Avoid necrotic center
- Insert biopsy needle through coaxial
- Fire needle to obtain core
- Remove and inspect core
- Repeat for 4-6 cores minimum
- Confirm adequate tissue obtained
- Remove coaxial cannula
- Apply pressure for hemostasis
- Post-procedure imaging (assess complications)
- Compression dressing
- Steri-strips to skin (no sutures usually needed)
Equipment Needed
Core needle system:
- 11-16 gauge biopsy needle
- Coaxial guiding cannula
- Specimen containers (formalin and sterile)
Image guidance:
- CT scanner or ultrasound
- Sterile probe covers if ultrasound
Key Technical Points
Optimize diagnostic yield:
- Target lesion periphery (viable tissue)
- Avoid cystic/necrotic areas
- Multiple cores through single tract
- Rotate needle between passes
Minimize complications:
- Meticulous hemostasis
- Avoid major neurovascular structures
Complications and Biopsy Errors
Mankin's Classification of Errors
Mankin identified major biopsy errors in 18.2% of referral cases. These errors are categorized:
Mankin's Biopsy Error Categories
| Error Type | Frequency | Consequence | Prevention |
|---|---|---|---|
| Wrong biopsy type | 30% of errors | Excisional biopsy of sarcoma | Use incisional or core for suspected sarcoma |
| Inappropriate approach | 28% of errors | Transverse incision, multi-compartment | Longitudinal incision, single compartment, resection field |
| Poor hemostasis | 25% of errors | Hematoma spreads tumor cells | Meticulous technique, avoid tourniquet, no drain |
| Inadequate tissue | 17% of errors | Non-diagnostic specimen | Adequate sample size, avoid necrosis, frozen confirmation |
Consequences of Biopsy Errors
Mankin's series showed that major biopsy errors led to:
- Altered treatment in 8.5% of patients (wider resection needed)
- Unnecessary amputation in 4.5% (contamination precluded salvage)
- Increased morbidity (re-operation, skin grafting, flap coverage)
- Delayed definitive treatment (waiting for wound healing)
- Tumor progression during delay
These catastrophic outcomes emphasize why tumor biopsies should be performed at specialized centers by surgeons with oncologic training.
Specific Complications
Early Complications
Hematoma:
- Most common early complication
- Spreads tumor cells to surrounding tissue
- Prevention: meticulous hemostasis, compression dressing
Infection:
- Mimics tumor progression
- Delays definitive treatment
- Prevention: sterile technique, prophylactic antibiotics
Fracture:
- Through cortical window in bone biopsy
- Prevention: small window, avoid stress risers, consider prophylactic fixation
Late Complications
Tumor seeding:
- Along biopsy tract (requires wide excision of tract)
- Into adjacent compartment (may preclude salvage)
- Prevention: proper technique, en bloc excision of tract
Non-diagnostic result:
- Inadequate tissue or sampling error
- Requires repeat biopsy
- Prevention: adequate sample, image guidance, pathologist communication
Altered treatment:
- Wider resection needed due to contamination
- Amputation instead of salvage
- Prevention: proper planning and execution
Case Example: Biopsy Error Cascade
The Transverse Incision Disaster
Case: A 25-year-old presents with a 8cm firm thigh mass. A general surgeon performs an excisional biopsy through a transverse incision (thinking it is a benign cyst). Pathology returns as high-grade undifferentiated pleomorphic sarcoma.
Consequences:
- Transverse incision violated anterior and posterior compartments
- Tumor was "shelled out" (not excised with margin)
- Hematoma tracked into both compartments
- Femoral vessels and sciatic nerve now in contaminated field
- Wide re-excision would require sacrifice of these structures
- Patient counseled for above-knee amputation
Correct approach would have been:
- Pre-operative MRI staging
- Core needle biopsy or incisional biopsy
- Longitudinal incision in planned resection field
- Wide resection with negative margins
- Limb salvage achieved
This case illustrates how a single poor decision (excisional biopsy, transverse incision) can convert limb salvage to amputation.
Postoperative Care
Post-Biopsy Care Protocol
Post-Biopsy Care Timeline
- Compression dressing maintained
- Monitor for bleeding/hematoma
- Ice for comfort if needed
- Analgesia (simple analgesics usually sufficient)
- Keep wound clean and dry
- Remove compression dressing at 48 hours
- Inspect wound for complications
- Light dressing over puncture site
- Resume normal activities as tolerated
- No heavy lifting or impact activities
- Await pathology results (5-10 days)
- Review wound at 7-10 days
- Remove sutures if open biopsy (10-14 days)
- Multidisciplinary team review when results available
- Plan definitive treatment
Wound Care Instructions
Patient instructions:
- Keep dressing clean and dry for 48 hours
- May shower after 48 hours (pat dry)
- No soaking (bath, swimming) for 2 weeks
- Watch for signs of infection (redness, swelling, discharge)
- Contact clinic if concerns arise
Activity Restrictions
Core needle biopsy:
- Resume normal activities next day
- Avoid strenuous exercise for 48-72 hours
- No restrictions on weight-bearing
Open biopsy:
- Limit activity for 1 week
- Consider protected weight-bearing if bone biopsy
- Avoid impact activities until wound healed
Outcomes
Biopsy Outcomes Overview
Core Needle Biopsy Outcomes
Diagnostic accuracy:
- Overall: 85-95% for sarcomas
- Sensitivity: 89-96%
- Specificity: 97-100%
- NPV: 85-92%
Complications:
- Overall: 3-5%
- Hematoma: 2-3% (mostly minor)
- Infection: less than 1%
- Major complications: less than 0.5%
Open Biopsy Outcomes
Diagnostic accuracy:
- Higher tissue yield improves diagnosis
- Near 100% when adequate tissue obtained
- May be required after non-diagnostic needle
Complications:
- Higher than needle biopsy
- Hematoma: 5-10%
- Wound complications: 2-5%
- Tumor seeding risk higher
- Longer recovery time
Evidence Base and Literature
CT-Guided Core Biopsy
Advantages of CT guidance:
- Bone visualization: See cortex, plan trajectory
- Avoidance of critical structures: 3D planning
- Confirmation of placement: Real-time imaging
- Deep lesions accessible: Pelvis, spine, retroperitoneum
- Reproducible approach: Coordinates documented
Technique:
- Patient positioning (prone, supine, lateral based on approach)
- Scout CT to plan trajectory
- Skin prep and local anesthesia
- Small nick incision with scalpel
- Coaxial needle placement under CT guidance
- Confirm position on CT
- Multiple cores through coaxial needle (4-6 cores)
- Post-biopsy CT to assess for complications
- Compression dressing
Coaxial Needle Technique
A coaxial needle system uses an outer guiding cannula through which the biopsy needle passes. This allows multiple cores through a single tract, reducing contamination and improving patient comfort. The guiding cannula is positioned under CT, then multiple cores are obtained without removing the guide. This is the standard technique for percutaneous bone biopsy.
Ultrasound-Guided Core Biopsy
Advantages of ultrasound:
- Real-time visualization: See needle advancing in real-time
- No radiation: Safe for multiple passes
- Vascular avoidance: Doppler identifies vessels
- Soft tissue detail: Excellent for superficial masses
- Portable: Can be done in clinic or OR
Technique:
- Identify lesion and vasculature on Doppler ultrasound
- Plan trajectory avoiding vessels
- Mark entry site
- Sterile prep and local anesthesia
- Visualize needle entry and advancement in real-time
- Multiple cores (3-5 minimum)
- Confirm hemostasis on ultrasound
- Compression dressing
Best for:
- Superficial soft tissue masses
- Vascular lesions (can avoid vessels)
- Pediatric patients (no radiation)
- Lesions near neurovascular bundles (real-time avoidance)
Fluoroscopy-Guided Biopsy
Limited role in musculoskeletal oncology:
- Primarily for spine lesions (transpedicular approach)
- Real-time guidance for needle placement
- Lower radiation than CT
- 2D imaging only (less accurate than CT 3D)
Collaboration with Tumor Centers
All suspected sarcomas should be discussed with a tumor center before biopsy. Referral is indicated for suspected bone sarcoma, soft tissue mass greater than 5cm or deep to fascia, imaging features of malignancy, failed primary treatment, complex anatomy (spine, pelvis), and metastatic disease staging.
The optimal referral is BEFORE biopsy. Many tumor centers prefer to perform the biopsy themselves. Referral after an inappropriate biopsy results in delayed treatment, increased morbidity, and potentially worse outcomes.
Tumor centers provide access to multidisciplinary tumor boards including orthopaedic oncologist, musculoskeletal radiologist and pathologist, medical oncologist, radiation oncologist, and plastic surgeon. Benefits include expert consensus, coordinated treatment planning, protocol-based therapy, access to clinical trials, and improved outcomes.
Mankin's Landmark Biopsy Study
- 329 patients referred after biopsy elsewhere analyzed
- 18.2% had major biopsy errors affecting treatment
- Altered treatment required in 8.5% of patients
- Unnecessary amputation in 4.5% due to biopsy complications
- Most common errors: wrong biopsy type (30%), inappropriate approach (28%), poor hemostasis (25%)
- Established principle that biopsy should be performed by definitive surgeon
Core Needle Biopsy Diagnostic Accuracy
- 152 musculoskeletal lesions biopsied with CT-guided core needle
- Overall diagnostic accuracy 90.1%
- Sensitivity for malignancy 89.6%, specificity 97.7%
- Non-diagnostic rate 6.6% (compared to 17% for FNA)
- Complications in 1.3% (all minor - small hematomas)
- Repeat biopsy needed in 10 cases (6.6%)
Impact of Unplanned Excision of Soft Tissue Sarcoma
- Compared 145 patients with unplanned excision to 225 with planned resection
- Local recurrence higher after unplanned excision (31% vs 11%)
- Re-excision achieved negative margins in only 45%
- Need for radiation therapy higher (72% vs 41%)
- Overall survival not significantly different (contamination affects local control)
- Unplanned excision remains independent predictor of local recurrence
Image-Guided Bone Biopsy Complications
- 256 CT-guided bone biopsies reviewed for complications
- Overall complication rate 3.5% (all minor)
- Hematoma most common (2.3%), all resolved spontaneously
- Infection in 0.4% (1 patient)
- No nerve injuries or vascular complications
- Diagnostic yield 89% (non-diagnostic rate 11%)
- Larger gauge needles (11-13G) had higher yield than smaller (14-16G)
MCQ Practice Points
High-Yield MCQ Topic: Mankin's Study
Q: What percentage of patients in Mankin's series had major biopsy errors?
A: 18.2% had major errors, leading to altered treatment in 8.5% and unnecessary amputation in 4.5%. Error categories: wrong type (30%), wrong approach (28%), poor hemostasis (25%), inadequate tissue (17%). The conclusion was that biopsies should be performed by the definitive surgeon.
High-Yield MCQ Topic: Core Biopsy Accuracy
Q: What is the diagnostic accuracy of image-guided core needle biopsy for musculoskeletal tumors?
A: 85-95% diagnostic accuracy with under 5% complication rate. This is higher than FNA (60-80%). Requires minimum 3-5 cores. Image guidance (CT or ultrasound) is preferred. It is the first-line technique for most musculoskeletal tumors.
High-Yield MCQ Topic: Incision Principles
Q: A general surgeon performs a biopsy for a suspected thigh sarcoma. Which represents a major error?
A: A transverse incision (NEVER acceptable). Must use longitudinal incision parallel to neurovascular bundle, in planned resection field, so entire tract can be excised en bloc. Transverse incisions contaminate multiple compartments and may necessitate amputation.
High-Yield MCQ Topic: Appropriate Biopsy Type
Q: A 60-year-old presents with a 7cm deep soft tissue mass. What is the most appropriate initial biopsy?
A: Core needle biopsy (image-guided). This is first-line for most lesions with 85-95% accuracy. Excisional biopsy would be a major error for a large deep mass (suspected sarcoma). Incisional biopsy is reserved for cases where needle is inadequate.
This section provides exam-focused practice points.
Australian Context
Sarcoma Referral Centers: Major Australian sarcoma centers include Peter MacCallum Cancer Centre (Melbourne), Chris O'Brien Lifehouse (Sydney), Princess Alexandra Hospital (Brisbane), and Royal Adelaide Hospital (Adelaide). These centers provide multidisciplinary sarcoma clinics, limb salvage expertise, and access to clinical trials.
Referral Pathways: In Australia, the optimal sarcoma care pathway involves early referral to a specialized center, ideally BEFORE biopsy. Many centers offer telehealth consultation for regional patients. The CanRefer system facilitates direct specialist referrals. General practitioners and surgeons can access tumor board review even if the patient is managed locally.
Guidelines: Cancer Australia's optimal care pathway for sarcoma emphasizes early referral and multidisciplinary care. Biopsy recommendations include percutaneous core needle first-line, with open biopsy by treating surgeon if needed. Quality indicators track inappropriate excisions and time to specialist review.
Management Considerations: The Australian Sarcoma Study Group (ASSG) recommends all suspected sarcomas be discussed at multidisciplinary meetings, with biopsy at treating center when possible. Standardized reporting of pathology and imaging is emphasized. PBS subsidies are available for chemotherapy agents (doxorubicin, ifosfamide, trabectedin, pazopanib) with authority applications requiring biopsy confirmation and staging.
This completes the Australian context discussion.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Classification Viva Question
"What are the indications for open incisional biopsy over core needle biopsy?"
Surgical Technique Viva Question
"You are performing an open biopsy of a proximal tibia lesion suspected to be osteosarcoma. Walk me through your surgical approach."
Outcomes Viva Question
"What is the reported diagnostic accuracy of core needle biopsy for musculoskeletal tumors, and what factors influence this?"
BIOPSY PRINCIPLES - EXAM DAY ESSENTIALS
High-Yield Exam Summary
Mankin's Biopsy Errors (MUST KNOW)
- •**18.2% major errors** in referral biopsies
- •**8.5% altered treatment**, 4.5% unnecessary amputation
- •Error types: wrong type (30%), wrong approach (28%), poor hemostasis (25%), inadequate tissue (17%)
- •Conclusion: **biopsy by definitive surgeon** or tumor center
Cardinal Biopsy Principles
- •**Longitudinal incision ONLY** - transverse is never acceptable
- •**Single compartment** approach - do not violate multiple planes
- •**Resection field trajectory** - entire tract excised en bloc
- •**Meticulous hemostasis** - hematoma spreads tumor cells
- •**No drains** (or drain exits through incision)
- •**Tumor center consultation** before biopsy
Biopsy Type Selection
- •**Core needle**: First-line, 85-95% accuracy, 4-6 cores minimum
- •**Incisional open**: If needle inadequate, longitudinal approach
- •**Excisional**: ONLY small superficial under 3cm low suspicion
- •**FNA**: Limited role, confirmatory only (60-80% accuracy)
- •**NEVER** excise suspected sarcoma - major error
Image Guidance
- •**CT-guided**: Bone lesions, deep masses, 3D planning
- •**Ultrasound-guided**: Superficial soft tissue, real-time, Doppler
- •**Fluoroscopy**: Limited role, spine transpedicular approach
- •Communicate with radiologist about resection field
Specimen Handling
- •**Fresh tissue** in sterile container for culture (not formalin)
- •**Minimum 1cm cube** or 3-5 cores for diagnosis
- •**Frozen section**: Confirm adequacy only (cannot diagnose sarcoma)
- •**Permanent H&E**: Standard diagnosis
- •**Immunohistochemistry**: Subtype sarcoma
- •**Molecular studies**: FISH, PCR if indicated
Indications for Biopsy
- •Deep soft tissue mass (below fascia)
- •Superficial mass over 5cm or growing
- •Bone lesion with aggressive features
- •Age-inappropriate lesion
- •Pathological fracture through lesion
- •Atypical imaging not fitting benign diagnosis
Specific Approaches
- •**Distal femur**: Anteromedial longitudinal (vastus medialis)
- •**Posterior thigh**: Posterior longitudinal (hamstring interval)
- •**Proximal tibia**: Anteromedial (pes anserinus)
- •**Pelvis**: CT-guided safer than open (complex anatomy)
- •**Spine**: Transpedicular CT-guided or posterior open
Common Exam Scenarios
- •**Referral after inappropriate biopsy**: Assess contamination, plan salvage
- •**Plan biopsy for suspected osteosarcoma**: Staging first, tumor center discussion, longitudinal approach
- •**Deep soft tissue mass**: Image-guided core needle first-line
- •**Transverse incision complication**: Multi-compartment contamination, amputation risk
References
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Mankin HJ, Lange TA, Spanier SS. The hazards of biopsy in patients with malignant primary bone and soft-tissue tumors. J Bone Joint Surg Am. 1982;64(8):1121-1127.
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Hau A, Kim I, Kattapuram S, et al. Accuracy of CT-guided biopsies in 359 patients with musculoskeletal lesions. Skeletal Radiol. 2002;31(6):349-353.
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Welker JA, Henshaw RM, Jelinek J, et al. The percutaneous needle biopsy is safe and recommended in the diagnosis of musculoskeletal masses. Cancer. 2000;89(12):2677-2686.
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Noria S, Davis A, Kandel R, et al. Residual disease following unplanned excision of soft-tissue sarcoma of an extremity. J Bone Joint Surg Am. 1996;78(5):650-655.
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Skrzynski MC, Biermann JS, Montag A, Simon MA. Diagnostic accuracy and charge-savings of outpatient core needle biopsy compared with open biopsy of musculoskeletal tumors. J Bone Joint Surg Am. 1996;78(5):644-649.
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Dupuy DE, Rosenberg AE, Punyaratabandhu T, et al. Accuracy of CT-guided needle biopsy of musculoskeletal neoplasms. AJR Am J Roentgenol. 1998;171(3):759-762.
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Fraser-Hill MA, Renfrew DL, Hilsenrath PE. Percutaneous needle biopsy of musculoskeletal lesions. 2. Cost-effectiveness. AJR Am J Roentgenol. 1992;158(4):813-818.
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Heslin MJ, Lewis JJ, Woodruff JM, Brennan MF. Core needle biopsy for diagnosis of extremity soft tissue sarcoma. Ann Surg Oncol. 1997;4(5):425-431.
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Pohlig F, Kirchhoff C, Lenze U, et al. Percutaneous core needle biopsy versus open biopsy in diagnostics of bone and soft tissue sarcoma: a retrospective study. Eur J Med Res. 2012;17:29.
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Ray-Coquard I, Montesco MC, Coindre JM, et al. Sarcoma: concordance between initial diagnosis and centralized expert review in a population-based study within three European regions. Ann Oncol. 2012;23(9):2442-2449.
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Mitsuyoshi G, Naito N, Kawai A, et al. Accurate diagnosis of musculoskeletal lesions by core needle biopsy. J Surg Oncol. 2006;94(1):21-27.
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Strauss DC, Qureshi YA, Hayes AJ, et al. The role of core needle biopsy in the diagnosis of suspected soft tissue tumours. J Surg Oncol. 2010;102(5):523-529.
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Domanski HA, Akerman M, Carlén B, et al. Core-needle biopsy performed by the cytopathologist: a technique to complement fine-needle aspiration of soft tissue and bone lesions. Cancer. 2005;105(4):229-239.
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Adams SC, Potter BK, Pitcher DJ, Temple HT. Office-based core needle biopsy of bone and soft tissue malignancies: an accurate alternative to open biopsy with infrequent complications. Clin Orthop Relat Res. 2010;468(10):2774-2780.
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Åkerman M, Domanski HA. The cytology of soft tissue tumours. Monogr Clin Cytol. 2003;16:1-116.
Key Australian References
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Australia and New Zealand Sarcoma Association (ANZSA). Guidelines for the management of soft tissue sarcoma. Available at: www.anzsa.org.au
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Cancer Australia. Optimal care pathway for people with sarcoma. Canberra: Cancer Australia, 2016.
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Victorian Comprehensive Cancer Centre. Sarcoma service referral guidelines. Melbourne: Peter MacCallum Cancer Centre, 2020.
Suggested Reading
- Enneking WF. Musculoskeletal Tumor Surgery, Volume 1. Churchill Livingstone; 1983. [Classic text on biopsy principles]
- Simon MA, Springfield D. Surgery for Bone and Soft-Tissue Tumors. Lippincott-Raven; 1998. [Comprehensive operative techniques]
- Grimer RJ, Carter SR, Pynsent PB. The cost-effectiveness of limb salvage for bone tumours. J Bone Joint Surg Br. 1997;79(4):558-561.