What is the diagnostic workup for a persistent swollen lymph node in the neck?

Diagnostic Workup for Persistent Swollen Lymph Node in the Neck

Any neck mass present for ≥2 weeks without significant fluctuation or of uncertain duration requires a thorough diagnostic workup to rule out malignancy, especially in patients over 40 years of age. 1

Initial Risk Assessment

High-Risk Historical Features:

• Mass present ≥2 weeks or of uncertain duration
• Absence of recent infection
• Age >40 years
• Tobacco and alcohol use
• Associated symptoms:
  • Sore throat/pharyngitis
  • Dysphagia
  • Otalgia ipsilateral to neck mass
  • Voice changes
  • Hearing loss ipsilateral to neck mass
  • Nasal obstruction/epistaxis ipsilateral to neck mass
  • Unexplained weight loss
  • History of head and neck malignancy

High-Risk Physical Examination Features:

• Fixation to adjacent tissues
• Firm consistency
• Size >1.5 cm
• Ulceration of overlying skin
• Reduced mobility of mass
• Oral cavity or oropharyngeal ulceration

Diagnostic Algorithm

Step 1: Complete Head and Neck Examination

• Thorough examination of all mucosal surfaces of head and neck
• Complete skin examination (patients with one skin cancer are at risk for others)
• Careful palpation of all cervical lymph node regions

Step 2: Imaging

• CT scan of neck, chest, and abdomen is mandatory 1
• Consider additional PET scan for more accurate staging if malignancy is suspected
• Ultrasound can be useful for initial evaluation, especially for:
  • Detecting and localizing enlarged nodes
  • Evaluating infiltration of adjacent structures
  • Guiding needle biopsies 2

Step 3: Tissue Diagnosis

• For persistent neck mass (>1 month), histological analysis is essential to rule out malignancy 3
• Excisional biopsy is preferred for definitive diagnosis, especially when lymphoma is suspected 3
• Fine-needle aspiration (FNA) may be used initially but has limitations:
  • If FNA of lymph nodes in head/neck region is negative but suspicion remains high, consider:
    • Repeat imaging
    • Repeat FNA
    • Open lymph node biopsy 1
  • If FNA is positive, perform imaging to determine size, number, and location of abnormal nodes

Step 4: Laboratory Testing

• Complete blood count
• Erythrocyte sedimentation rate (ESR)
• Blood chemistry including:
  • Glucose
  • Alkaline phosphatase
  • Lactate dehydrogenase
  • Liver enzymes
  • Albumin 1
• Screening for hepatitis B, hepatitis C, and HIV

Special Considerations

When to Avoid Empiric Antibiotics

• In the absence of signs and symptoms suggesting infection, empiric antibiotics should be avoided
• If antibiotics are prescribed for suspected infection, patient should be reassessed within 2 weeks
• If mass has not completely resolved after antibiotics, proceed with workup for malignancy 1

Malignancy Rates

• Studies show approximately 38% of persistent cervical lymphadenopathy cases are malignant:
  • About half are metastatic disease
  • About half are malignant lymphoma 4
• Age range for malignancy is broad (15-92 years) but risk increases with age 4

Common Diagnoses in Persistent Neck Lymphadenopathy

Malignant Causes:

• Metastatic squamous cell carcinoma (especially from head and neck primary)
• Lymphoma (Hodgkin's and non-Hodgkin's)
• Thyroid cancer
• Salivary gland tumors

Benign Causes:

• Reactive lymphadenopathy
• Tuberculous lymphadenitis
• Cat-scratch disease
• Infectious mononucleosis
• Sarcoidosis

Remember that any neck mass that persists beyond 2 weeks, especially in adults over 40 years of age, should be considered suspicious for malignancy until proven otherwise. Early diagnosis significantly improves outcomes through earlier treatment and potential reduction in distant metastases.