What is the approach to evaluating a patient with a single palpable lymph node, considering factors such as location, size, and associated symptoms, as well as the patient's age, sex, and past medical history?

Approach to a Single Palpable Lymph Node

Fine-needle aspiration (FNA) is the mandatory first diagnostic step for a single palpable lymph node, particularly when it is >1.5 cm, firm, or exhibits concerning features, as this provides rapid tissue diagnosis with 91.7% sensitivity and 98.2% specificity for malignancy. 1

Initial Clinical Assessment

Critical Physical Examination Features

Document the following characteristics systematically:

• Size: Nodes >1.5 cm are suspicious for malignancy; nodes >2 cm are particularly concerning 2, 3
• Texture: Firm or hard consistency suggests malignancy, though HPV-positive head and neck cancers may present as soft, cystic masses 2
• Mobility: Reduced mobility in longitudinal and transverse planes indicates possible malignancy 2
• Location: Supraclavicular, epitrochlear (>5 mm), popliteal, and iliac nodes are abnormal and warrant immediate investigation 4
• Number and laterality: Single versus multiple nodes, unilateral versus bilateral presentation 2, 1
• Skin changes: Ulceration or fixation to overlying skin 2
• Associated findings: Matted or grouped nodes, edema of surrounding tissues 2

Essential History Elements

• Duration: Lymphadenopathy persisting >4 weeks requires imaging and laboratory workup 3
• Age: Patients >40 years have increased malignancy risk 2, 4
• Risk factors: Tobacco use, alcohol abuse, immunosuppression, sexual history (HPV risk), occupational exposures 2
• Constitutional symptoms: Fever, night sweats, unintentional weight loss (B symptoms suggest lymphoma or advanced malignancy) 2, 3
• Regional symptoms: For head/neck nodes—hoarseness, otalgia, dysphagia, hemoptysis; for inguinal nodes—genital lesions, lower extremity skin changes 2, 1

Diagnostic Algorithm

Step 1: Risk Stratification

High-risk features requiring immediate FNA 2, 1:

• Size >1.5 cm
• Firm or hard texture
• Reduced mobility
• Supraclavicular, epitrochlear, or other abnormal location
• Duration >4 weeks
• Associated constitutional symptoms
• Patient age >40 years with risk factors

Step 2: Fine-Needle Aspiration

FNA should be performed before any surgical intervention to avoid unnecessary morbidity and guide appropriate management 5, 6. This is particularly critical because:

• 30-50% of palpable lymphadenopathy is inflammatory rather than malignant 2, 5
• FNA provides rapid diagnosis with excellent sensitivity/specificity 1
• Immediate surgical excision without FNA leads to unnecessary morbidity 6

Step 3: Imaging Considerations

Obtain CT or MRI when 2, 1:

• Node is ≥4 cm (perform imaging before FNA to assess extent)
• Concern for deeper involvement (pelvic, retroperitoneal)
• Positive FNA requiring staging
• Difficult clinical assessment due to body habitus or prior surgery

Important limitation: CT and MRI have limited accuracy for non-palpable disease 2, 5

Step 4: Management Based on FNA Results

If FNA is Positive for Malignancy:

• Initiate immediate oncologic management based on primary malignancy identified 1, 6
• For penile cancer: immediate inguinal lymph node dissection 2, 1
• Obtain staging imaging as appropriate 1

If FNA is Negative:

Do not assume benign disease—confirm with excisional biopsy or careful surveillance, particularly if the node has heterogeneous appearance or concerning features 5, 1, 6

• Excisional biopsy indications: Persistent lymphadenopathy despite treatment, heterogeneous appearance, high clinical suspicion despite negative FNA 6, 7
• Surveillance protocol: Clinical examination every 3 months; re-biopsy if nodes enlarge or new systemic symptoms develop 1

Location-Specific Considerations

Head and Neck Nodes

• Jugulodigastric nodes up to 1.5 cm may be normal 2
• Examine oral cavity, oropharynx, nasopharynx, larynx for primary lesions 2
• Consider HPV-related oropharyngeal cancer even in younger patients without traditional risk factors 2

Inguinal Nodes

• Search for primary lesions: genitalia, perineum, lower extremities, perianal region 1
• Consider sexually transmitted infections (lymphogranuloma venereum presents with tender unilateral inguinal lymphadenopathy) 1
• For nodes <4 cm, FNA is standard; for ≥4 cm, obtain imaging first 5, 1

Supraclavicular Nodes

• Always abnormal and highly suspicious for malignancy 4, 8
• Require immediate FNA and staging workup 4

Common Pitfalls to Avoid

• Never assume all palpable lymphadenopathy is malignant: 30-50% of cases are inflammatory, but systematic evaluation is still mandatory 5, 6
• Never proceed to immediate surgical excision without FNA: This causes unnecessary morbidity and delays diagnosis 5, 6
• Never use corticosteroids empirically: They mask histologic diagnosis of lymphoma and other malignancies 3, 4
• Never rely on antibiotics as a diagnostic test: While a 6-week antibiotic course was historically used to distinguish reactive from malignant nodes, FNA is now the preferred approach 2
• Never ignore negative FNA in high-risk patients: Confirm with excisional biopsy if clinical suspicion remains high 5, 1, 6

Laboratory Workup for Persistent Lymphadenopathy

When lymphadenopathy persists >4 weeks or systemic symptoms are present 3:

• Complete blood count
• C-reactive protein and erythrocyte sedimentation rate
• Tuberculosis testing (particularly in endemic areas)
• Additional tests based on clinical context (HIV, EBV, CMV serology; autoimmune markers)