What are the likely causes and initial work‑up for a solitary, tender, mobile left anterior neck mass present for 24 hours in a patient without obvious upper or lower respiratory infection signs?

Acute Tender Anterior Neck Mass: Likely Causes and Management

In a patient with a 24-hour tender, mobile anterior neck lymph node without respiratory infection signs, the most likely cause is reactive lymphadenopathy from an occult local infection, but you must immediately assess for high-risk features that would trigger urgent malignancy work-up rather than observation. 1

Immediate Risk Stratification

The 24-hour duration places this patient in a low-risk category for malignancy, as high-risk features include mass present ≥2 weeks without fluctuation. 1, 2 However, you must systematically evaluate for other concerning features:

High-Risk Features That Would Change Management:

• Size >1.5 cm in greatest dimension 1, 2
• Firm or hard consistency (versus soft/rubbery) 1, 2
• Fixed to adjacent structures rather than mobile 1, 2
• Overlying skin ulceration 1, 2
• Age >40 years with tobacco/alcohol use 1
• Associated symptoms: throat pain, dysphagia, ipsilateral ear pain, voice changes, unexplained weight loss 1

Most Likely Causes at 24 Hours

Primary Differential:

• Reactive lymphadenopathy from occult infection (dental, scalp, pharyngeal, skin) - most common cause of acute tender adenopathy 3, 4
• Viral lymphadenitis (including early infectious mononucleosis) 3, 4
• Bacterial lymphadenitis (Staphylococcus, Streptococcus) with early presentation 3, 4
• Cat-scratch disease (Bartonella henselae) - inquire about feline exposure 3

Less Likely at 24 Hours But Must Consider:

• Acute suppurative lymphadenitis progressing to abscess 3
• Mycobacterial infection (typically subacute, not 24 hours) 3

Initial Work-Up Algorithm

Step 1: Detailed History

Document the following specific features (required by guidelines): 2

• Exact size in centimeters (measure with calipers/ruler)
• Consistency: soft, firm, or hard
• Mobility: mobile versus fixed to underlying structures
• Overlying skin: warmth, erythema, ulceration
• Precise duration and fluctuation pattern
• Tenderness level
• Associated symptoms: fever, night sweats, weight loss, throat pain, dysphagia, ear pain, voice changes 1
• Infectious exposures: recent dental work, scalp lesions, cat scratches, tick bites, tuberculosis contacts 3
• Risk factors: age, tobacco, alcohol use 1

Step 2: Targeted Physical Examination

• Examine the entire neck for additional masses 1
• Inspect oral cavity and oropharynx for ulcers, tonsillar asymmetry, masses 1
• Examine scalp and face for skin lesions, wounds, or infections 3
• Check for dental pathology 3
• Palpate for hepatosplenomegaly (suggests systemic process) 3

Step 3: Management Based on Findings

If Clear Infectious Features Present:

Signs include: warmth, erythema of overlying skin, acute onset, marked tenderness, fever, tachycardia 5, 2

• One course of broad-spectrum antibiotics is reasonable (e.g., amoxicillin-clavulanate for 7-10 days) 2, 5
• Mandatory re-evaluation in 2 weeks: if not completely resolved, initiate full malignancy work-up 2, 5
• Partial resolution requires additional evaluation because infection may coexist with malignancy 2
• After complete resolution, follow-up at 2-4 weeks to monitor for recurrence 2

If NO Clear Infectious Features:

Avoid empiric antibiotics - they delay diagnosis, promote resistance, and provide false reassurance 1, 2, 5

• Observation with close follow-up in 1-2 weeks if no high-risk features present 1, 2
• Document a clear follow-up plan and criteria that would trigger urgent re-evaluation 1
• Patient education: instruct to return immediately if mass enlarges, becomes fixed, or new symptoms develop 1

If ANY High-Risk Feature Present:

Proceed immediately to malignancy work-up: 1, 2

1. Contrast-enhanced CT of the neck (or MRI if CT contraindicated) 2, 5
2. Targeted endoscopic examination of larynx, base of tongue, and pharynx (perform or refer urgently) 2, 5
3. Fine-needle aspiration (FNA) - preferred over open biopsy (95% adequacy, 94-96% accuracy) 1, 2
4. Specialist referral within days (otolaryngology or oncology) 2, 6

Critical Pitfalls to Avoid

• Do NOT assume tenderness equals infection - malignant nodes can be tender, especially with rapid growth or necrosis 1
• Do NOT prescribe antibiotics without clear infectious signs - this is the most common error leading to delayed cancer diagnosis 1, 2, 5
• Do NOT perform open biopsy before imaging, FNA, and endoscopic evaluation - premature biopsy impairs staging and treatment 1, 2, 5
• Do NOT assume cystic masses are benign - HPV-positive oropharyngeal cancer commonly presents as cystic cervical metastases mimicking branchial cleft cysts 1, 2, 5
• Do NOT delay work-up in patients >40 years - up to 80% of cystic neck masses in this age group are malignant 6

When to Escalate Urgently

Immediate specialist referral if: 2, 6

• Mass persists or enlarges beyond 2 weeks 1, 2
• Any high-risk physical examination feature develops 1, 2
• Patient develops throat pain, dysphagia, ear pain, or voice changes 1
• Incomplete resolution after appropriate antibiotic course 2