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Indications / Contraindications
Indications
- Staging of nodal metastasis — known or suspected primary malignancy
- Suspected lymphoma (FNA for initial evaluation; CNB for subtyping + flow cytometry)
- Non-palpable or non-diagnostic palpation-guided biopsy of a lymph node
- Treatment planning — extent of nodal disease, pre-operative chemotherapy/radiation decision-making
- Suspected infectious lymphadenitis — identify organism, tailor antibiotics
- Recurrent lymphadenopathy with prior non-diagnostic biopsy
- HPV-related oropharyngeal SCC — p16 IHC on CNB alters staging
Contraindications + Needle Selection
- SIR Cat 1 (FNA): No specific coagulation requirements
- SIR Cat 2 (CNB): INR <2.0, platelets >50,000
- No safe access path (lesion surrounded by critical vessels with no alternate route)
- Uncooperative patient
- FNA preferred for: Superficial lymph nodes, suspected mets with proven primary, lesions near critical neurovascular structures
- CNB preferred for: Suspected lymphoma, non-diagnostic FNA, special markers (p16), large masses, bony lesions with soft tissue component
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Pre-Procedure Checklist
Review prior imaging. Confirm target node on US — assess cortical thickness, echogenicity, loss of fatty hilum, and vascularity. Cross-sectional imaging (CT/MRI) helpful to characterize nodal disease burden before biopsy.
Labs for CNB. INR <2.0, platelets >50,000. No routine coagulation labs required for FNA. Anticoagulation holds per SIR guidelines.
Consent. Hematoma, bleeding, pain, infection, non-diagnostic specimen (10–20%), false negative, vascular injury (carotid, jugular), tumor seeding (0.0011% CNB, 0.00012% FNA).
Notify pathology. If lymphoma is suspected, call pathology in advance — specimen must go in fresh saline or RPMI (NOT formalin) for flow cytometry. ROSE improves yield significantly.
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Relevant Anatomy
Nodal Stations
- Cervical nodes (levels I–V): Mobile nodes — real-time US essential. Target cortex, not fatty hilum. Avoid adjacent carotid and jugular with Doppler.
- Axillary nodes: Patient arm overhead or abducted. Target cortex >3 mm. Doppler before each pass to avoid axillary vein.
- Inguinal/femoral nodes: Identify and avoid femoral vessels. Large superficial nodes are readily accessible.
- Supraclavicular nodes: Avoid subclavian vessels; pneumothorax risk with deep passes — shallow angle.
Key US Features of Abnormal Nodes
- Loss of fatty hilum — abnormal; correlates with cortical replacement by tumor
- Cortical thickening >3 mm or eccentric cortical bulge — suspicious
- Rounded shape (short-to-long axis ratio >0.5) — abnormal
- Peripheral / chaotic vascularity on Doppler (vs. normal hilar flow)
- Central necrosis — large anechoic center; target viable peripheral cortex for FNA/CNB
- Cystic change — classic for HPV-related oropharyngeal SCC nodal mets
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Technique
Default RadCall approach · share your own below
Supplies
Linear US probe (high-freq)
Sterile US probe cover + gel
25g needle ×3 (FNA)
5 mL syringe
18g core biopsy device (CNB)
1% lidocaine + 25g needle
ChloraPrep / iodine prep
Sterile drape + towels
Scalpel (11-blade or 18g nick for CNB)
Glass slides + 95% ethanol
Fresh saline specimen tube (lymphoma)
10% formalin jars (carcinoma/IHC)
RPMI tube (flow cytometry / molecular)
Steps
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Position and preliminary US
Supine. For cervical/parotid nodes: head turned away from operator (roll patient slightly to get horizontal needle angle — avoids hitting the table with the needle back-end). Pillow/wedge under ipsilateral shoulder if needed. Perform Doppler survey — identify target node, its cortical thickness, adjacent carotid/jugular, and best approach angle. Note: cervical lymph nodes are mobile and will move away from an advancing needle.
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Sterile prep and local anesthesia
ChloraPrep prep. Sterile towels (preferred over eye-hole drapes for head/neck — maintains adequate field without completely covering the face). Sterile probe cover. 1% lidocaine — skin wheal, then deeper injection under US guidance using 25g 2.5-inch needle to planned depth.
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FNA of the node
25g needle, freehand under real-time US. Target the cortex of the node, not the fatty hilum — cortex contains the pathologic cells. For irregular/necrotic nodes: target viable peripheral cortex, avoiding central necrosis. Perform 30–60 needle strokes within the cortex with or without aspiration. Gently rotate needle. For mobile nodes — approach from a more medial angle to "pin" the node against the deeper tissues.
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CNB — when FNA is insufficient or lymphoma suspected
18g core biopsy device. Small skin nick with 18g needle or 11-blade scalpel. Advance to leading edge of node under US. Measure throw distance on US if using a fixed-throw device — confirm no vessel within the throw path. Fire and obtain specimen. 2–3 cores minimum. Post-procedure US to check for hematoma. Hold manual pressure 5–10 minutes after CNB.
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Post-procedure check
Post-procedure US to check for hematoma or active bleeding. Sterile dressing. Cold compress. Monitor for 30 minutes minimum before discharge.
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Troubleshooting
Problem
Node moves away from the advancing needle
Likely cause: Superficial nodes are mobile — particularly cervical nodes. Needle pressure displaces the node.
Next step: Approach from a slightly medial angle to "pin" the node against deeper tissues (muscle, fascia). Ultrasound allows you to see the displacement in real time and adjust. For very mobile nodes, a more lateral, nearly tangential approach to the cortex prevents the node from rolling away.
Problem
Non-diagnostic FNA (necrotic center sampled)
Likely cause: FNA targeted the central necrotic area of a large or metastatic node instead of the viable cortex.
Next step: US is particularly valuable for identifying viable cortex vs. necrotic center in real time. Color Doppler can identify vascularized (viable) nodal tissue. For largely necrotic masses, target the peripheral rind of enhancing tissue. If still non-diagnostic — CNB from viable tissue, or consider PET-CT co-registration to identify metabolically active zones.
Problem
Suspected lymphoma — FNA returns "atypical lymphocytes, cannot exclude lymphoma"
Likely cause: FNA cytology cannot architecturally subtype lymphoma. Flow cytometry may be insufficient for subtyping without tissue architecture.
Next step: Proceed to CNB. Submit additional specimen in fresh saline or RPMI (NOT formalin) for flow cytometry and immunophenotyping. 2–3 cores are usually sufficient for lymphoma subtyping. If CNB is technically unsafe due to nodal location, discuss with hematology/oncology — surgical excisional biopsy may be required for definitive subtyping.
Problem
Carotid artery proximity — concern for arterial injury
Likely cause: Target node or lesion is adjacent to the carotid sheath. Deep approaches carry higher vascular risk.
Next step: Doppler mapping is essential before every pass. Use real-time Doppler to confirm the carotid is not in the planned path. Consider FNA-only (no CNB) for nodes immediately adjacent to the carotid — smaller gauge = lower arterial injury risk.
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Complications
Hemorrhagic & Vascular
- Small hematoma — most common; compression + cold compress; self-limiting
- Carotid / jugular injury — prevented by Doppler planning; rarely requires intervention with FNA gauge
Neurologic & Other
- Vasovagal reaction — common for neck procedures; manage supine + leg elevation
- Infection — rare; no routine prophylaxis
- Tumor seeding — 0.00012% (FNA), 0.0011% (CNB). Clinically relevant in high-grade malignancies; coaxial technique for CNB minimizes tract contamination.
- Non-diagnostic specimen — 10–20%; related to necrotic sampling or technique. Repeat with ROSE or proceed to CNB.
- Pneumothorax — risk with supraclavicular node passes; use shallow angle and Doppler to stay clear of thoracic apex
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Post-Procedure Care
Monitoring
- US-guided FNA/CNB: 30 min observation; post-procedure US to check for hematoma
- Assess for swelling at biopsy site before discharge
Discharge + Follow-up
- Outpatient discharge when asymptomatic, hemostasis confirmed, no airway concerns
- Return precautions: rapidly expanding neck swelling, breathing difficulty, severe pain, fever
- Pathology results in 2–5 business days (IHC/flow may take longer — notify ordering provider)
- Lymphoma subtyping (flow + IHC) may require 5–7 business days; coordinate with hematology/oncology for expedited review
- Non-diagnostic result — discuss with ordering team: repeat biopsy, alternative target, or surgical excisional biopsy
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Critical Pearls
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Always review pre-procedure cross-sectional imaging first: Confirm the target is a true lesion. Identify pseudo-lesions (asymmetric pterygoid venous plexus is the classic pitfall). A non-diagnostic biopsy of a pseudo-lesion exposes the patient to unnecessary risk and delays diagnosis.
✦
Look for a safer lesion that yields the same diagnosis: If a superficial neck node and a retropharyngeal mass are both pathologic, biopsy the neck node. Same diagnostic information, far less risk.
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US real-time advantage for mobile nodes: Cervical nodes displace with needle pressure — real-time US lets you track and follow the node. Target the cortex, not the fatty hilum.
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CNB is required for lymphoma subtyping: FNA cytology is sufficient for initial diagnosis in some cases, but subtyping requires flow cytometry and architectural evaluation of core tissue. Submit in saline, never formalin. Call pathology before the procedure to confirm their protocol.
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For p16 / HPV-related oropharyngeal SCC: CNB is preferred to FNA when specific molecular markers (p16 IHC) are required for staging. This changes treatment planning and should be discussed with the ordering oncologist.
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Know your throw distance before firing CNB: For superficial nodes, measure the distance from needle tip to the far wall of the node on US. If the throw distance of your device exceeds this, the needle will fire through the node into adjacent structures. Coaxial technique or manual (non-spring-loaded) device gives better control near critical structures.
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Necrotic nodes require targeted sampling: Central necrosis yields acellular debris — non-diagnostic. Use color Doppler to target the vascularized cortex. For largely necrotic masses, PET-CT can identify metabolically active regions to guide targeting.
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Delayed pseudoaneurysm after deep H&N CT biopsy: Internal maxillary artery pseudoaneurysm has been reported as a delayed complication of paramaxillary approach. Any patient with sentinel oral hemorrhage after deep neck biopsy requires CTA and referral for endovascular treatment.
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Specimen Handling
FNA Cytology
- Suspected carcinoma / metastasis: Smear on glass slides → 95% ethanol (Pap stain) or air-dry (Diff-Quik); cell block in RPMI for IHC
- Suspected lymphoma: Deposit directly in fresh saline or RPMI — do NOT use formalin. Flow cytometry requires viable cells. Coordinate with pathology before procedure to confirm protocol.
- Suspected infection: Sterile saline or culture media. Gram stain, AFB smear, fungal culture as appropriate. Send swab for NAAT if TB suspected.
CNB Histology
- Carcinoma / IHC / p16: 10% formalin — architectural analysis, IHC, p16 for HPV-oropharyngeal SCC
- Lymphoma subtyping: Fresh saline or RPMI (NOT formalin) for flow cytometry + IHC. Confirm with pathology. Minimum 2–3 cores for subtyping.
- Molecular / NGS: RPMI or snap-freeze for targeted sequencing on indeterminate lesions
- Label containers immediately at time of biopsy — never batch-label after the procedure
Container Summary by Clinical Scenario
| Clinical Suspicion | Container | Notes |
|---|---|---|
| Metastatic carcinoma | 10% formalin (CNB) + RPMI cell block (FNA) | Standard; IHC for primary identification |
| Lymphoma | Fresh saline / RPMI — NOT formalin | Flow cytometry requires viable cells |
| p16 / HPV-SCC staging | 10% formalin | IHC on CNB core; confirm p16 protocol with path |
| Infectious lymphadenitis | Sterile saline or culture media | Gram, AFB, fungal cultures; consider NAAT for TB |
| Molecular / NGS | RPMI or fresh snap-freeze | 18g CNB preferred for nucleic acid yield |
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References & Resources
Primary sources · Key data · Related procedures
Key Guidelines
- SIR Standards of Practice for Image-Guided Percutaneous Biopsy
- ESUR Guidelines for Image-Guided Lymph Node Biopsy
Primary References
- Gupta S et al. Percutaneous biopsy of mediastinal lesions: endoscopic ultrasound versus CT-guided biopsy. Ann Oncol. 2008;19(9):1649-1651.
- Rotenberg G et al. CT-guided biopsy of mediastinal masses. Clin Radiol. 2009;64(4):346-350.
- Dewhurst CE et al. CT-guided core needle biopsy of lymph nodes. AJR Am J Roentgenol. 2011;197(3):W461-465.