Workup for Lymph Node with Overlying Skin Discoloration
Immediate Priority: Exclude Malignancy
A lymph node with overlying skin discoloration requires urgent evaluation for malignancy, as skin ulceration overlying a neck mass indicates metastatic cancer that has broken through the lymph node capsule and directly invaded the skin, or represents a cutaneous malignancy with direct extension into the neck. 1
High-Risk Features Requiring Immediate Action
The presence of skin discoloration/ulceration is itself a red flag that mandates aggressive workup. Additional concerning features include:
- Size >1.5 cm 1
- Firm or hard consistency 1
- Fixation to adjacent tissues (reduced mobility) 1
- Duration ≥2 weeks 1
- Age >40 years 1
- Tobacco and/or alcohol use 1
Algorithmic Workup Approach
Step 1: Confirm Tissue Diagnosis
- Fine-needle aspiration (FNA) is strongly preferred over open biopsy for initial tissue sampling 1, 2, 3
- Open biopsy should be avoided as it can complicate subsequent treatment and delay definitive care 1
- Send tissue for:
Step 2: Imaging Studies
- Contrast-enhanced CT of neck (or MRI) is mandatory to assess extent of disease and identify primary tumor 1, 2, 3
- PET-CT should be considered to identify occult primary malignancy and assess for distant metastases 1, 2
- For melanoma specifically: chest imaging and consideration of brain MRI if any neurologic symptoms 1
Step 3: Targeted Physical Examination
- Direct visualization of upper aerodigestive tract including larynx, base of tongue, and pharynx by otolaryngologist 3
- Complete skin examination to identify primary melanoma or other cutaneous malignancy 1
- Examination of all lymph node basins 1, 3
Step 4: Laboratory Testing
- Complete blood count, comprehensive metabolic panel 3
- Lactate dehydrogenase (LDH) - prognostic marker for lymphoma and melanoma 1, 3
- Hepatitis B, C, and HIV serology if malignancy confirmed and treatment planned 3
- Tuberculosis testing (PPD or IGRA) if granulomatous disease suspected 4
Critical Differential Diagnoses
Malignancy (Most Likely)
- Metastatic squamous cell carcinoma from head/neck primary 1, 2
- Melanoma with in-transit metastases or direct skin invasion 1
- Skin discoloration may represent melanoma pigmentation
- Requires complete dermatologic examination 1
- Cutaneous lymphoma (CD30+ lymphoproliferative disorders, anaplastic large cell lymphoma) 1
- Lymphoma with extranodal extension 3
Infectious Causes (Less Likely but Important)
- Nontuberculous mycobacterial (NTM) infection 4
- More common in children 1-5 years old
- Typically unilateral, may have violaceous skin discoloration
- Excisional biopsy is treatment of choice (95% success rate) 4
- Tuberculosis 4
- Requires PPD/IGRA testing
- Critical to distinguish from NTM for public health tracking 4
- Cat-scratch disease (Bartonella henselae) 5, 6, 7
Common Pitfalls to Avoid
- Never prescribe empiric antibiotics without clear signs of acute bacterial infection (fever, rapid onset, tenderness, erythema), as this delays cancer diagnosis 1, 2
- Do not assume cystic appearance on imaging is benign - HPV-positive oropharyngeal cancer frequently presents as cystic cervical metastases mimicking branchial cleft cysts 2
- Avoid corticosteroids - they mask histologic diagnosis of lymphoma and other malignancies 8, 9
- Do not rely on normal laboratory values - they provide false reassurance and do not exclude malignancy 2
- Partial resolution after antibiotics does not exclude malignancy - infection can coexist with underlying cancer 2, 3
Urgent Specialist Referral
Immediate referral to otolaryngology (head/neck surgery) or surgical oncology is mandatory for any lymph node with overlying skin changes 1, 2, 3. This is not a "wait and see" scenario - skin involvement indicates advanced local disease requiring urgent evaluation and treatment planning.