What is the appropriate work‑up for a palpable lump at the proximal clavicle in the lower neck?

Work-Up of a Lump at the Proximal Clavicle/Lower Neck

Begin with ultrasound as the initial imaging modality, followed by contrast-enhanced CT neck if the mass is suspicious, and proceed to fine-needle aspiration for tissue diagnosis when malignancy cannot be excluded. 1, 2

Initial Clinical Assessment

Identify high-risk features that mandate urgent evaluation:

• Duration ≥2 weeks without resolution or uncertain duration strongly suggests malignancy over reactive lymphadenopathy 1
• Firm consistency, fixation to adjacent tissues, size >1.5 cm, or skin ulceration are physical examination findings that increase malignancy risk 1
• Nontender masses are more suspicious for malignancy than tender masses 2
• Age >40 years with persistent mass dramatically shifts the differential toward malignancy, as supraclavicular masses in adults are malignant in approximately 79% of cases 3

Do NOT prescribe empiric antibiotics unless clear infectious signs are present (fever, erythema, fluctuance), as this delays diagnosis and may partially treat infection overlying an underlying malignancy 1

Imaging Algorithm

First-Line: Ultrasound

Ultrasound is the preferred initial imaging modality for neck masses because it:

• Distinguishes solid from cystic lesions 1
• Identifies lymph node architecture and vascularity 4, 5
• Detects nonpalpable pathologic nodes (ultrasound has 100% sensitivity vs. 33% for palpation in detecting supraclavicular metastases) 5
• Guides subsequent fine-needle aspiration 1, 4

Second-Line: Contrast-Enhanced CT Neck

If ultrasound shows suspicious features or cannot definitively characterize the mass, proceed immediately to contrast-enhanced CT neck (or MRI neck with contrast if CT contraindicated) 1, 2

CT provides:

• Precise anatomic localization and relationship to adjacent structures 2
• Assessment for nodal necrosis, a hallmark of metastatic disease 2
• Evaluation of the entire neck and upper mediastinum to identify occult primary tumors 2, 3

Critical pitfall: Supraclavicular masses have a high probability of originating from primary malignancies below the clavicle (lung, breast, gastrointestinal tract account for 94 of 117 metastatic cases in one series), so chest CT should be included in the same imaging session 3

Tissue Diagnosis

Fine-needle aspiration (FNA) is the initial pathologic test once imaging is complete 2, 4, 5

• FNA is rapid, cost-effective, and has high sensitivity/specificity for malignancy 2
• Ultrasound-guided FNA is preferred over palpation-guided biopsy for accuracy 5
• Cytologic diagnosis is mandatory in the majority of supraclavicular masses, as 79% represent the first manifestation of disease 3

Open excisional biopsy should only be performed after FNA and imaging are complete and diagnosis remains uncertain 2

Special Considerations

Left vs. Right Supraclavicular Location

• Left supraclavicular masses (Virchow's node) are significantly more likely to represent genitourinary or gastrointestinal malignancies 3
• Right-sided masses more commonly represent lung or breast primaries 3

Rare Benign Entities

• Levator claviculae muscle is a rare anatomic variant that can mimic a supraclavicular mass; it appears as a cylindrical structure extending from C6 transverse process to the clavicle on CT/MRI 6
• Tuberculosis is the most common benign etiology in nonmalignant supraclavicular masses (11 of 29 cases in one series) 3

Timeline for Evaluation

Complete the diagnostic work-up within 1-2 weeks maximum 2

• Delays in diagnosis adversely affect treatment outcomes and prognosis in malignancy 2
• If a mass persists beyond 2-3 weeks without resolution, malignancy must be excluded 1, 2

Common Pitfalls to Avoid

• Do not rely on palpation alone: Only 33% of supraclavicular metastases are palpable, and nodes must be ≥22 mm to have a 50% chance of detection by palpation 5
• Do not delay imaging with a trial of antibiotics unless clear infectious signs are present 1
• Do not stop at neck imaging: Extend imaging to chest and upper abdomen given the high frequency of infraclavicular primary malignancies 3
• Do not perform open biopsy before imaging and FNA 2