What is the recommended workup for mediastinal and lower cervical lymphadenopathy (lymph node enlargement)?

Workup of Mediastinal and Lower Cervical Lymphadenopathy

The recommended workup for mediastinal and lower cervical lymphadenopathy should include excisional lymph node biopsy, contrast-enhanced CT of chest/abdomen/pelvis, and PET/CT scan as the core diagnostic procedures to determine etiology and guide treatment decisions. 1

Initial Assessment

History and Physical Examination Focus Points

• Document specific risk factors:
  • History of malignancy (especially lung cancer, lymphoma)
  • Infectious disease exposure (tuberculosis, fungal infections)
  • Autoimmune disorders
  • Immunosuppression status (HIV, medications)
  • Systemic symptoms: fever, night sweats, weight loss, fatigue
  • Tobacco and alcohol use 1

Physical Examination Specifics

• Complete examination of all lymph node regions
• Document size, consistency, mobility, tenderness, and number of nodes
• Thorough examination of head and neck, including oral cavity
• Skin examination for lesions suggestive of underlying disease
• Lung and abdominal examination 1, 2

Core Diagnostic Procedures

Imaging

1. Contrast-enhanced CT scan of chest, abdomen, and pelvis

   • Essential first-line imaging modality
   • Assess size, number, and distribution of lymph nodes
   • A mediastinal lymph node is considered suspicious when smallest diameter exceeds 10mm 1
   • Evaluate for primary lesions in lungs or other organs

2. PET/CT scan

   • Recommended for functional assessment of lymphadenopathy
   • Particularly valuable for detecting malignancy
   • Helps distinguish between benign and malignant causes
   • Guides biopsy site selection 1

3. Neck ultrasound

   • Particularly useful for lower cervical lymphadenopathy
   • Can guide fine needle aspiration
   • High sensitivity for detecting cervical lymph node involvement 3

Tissue Diagnosis

1. Excisional lymph node biopsy

   • Gold standard for diagnosis
   • Preferred over fine-needle aspiration for initial evaluation 1
   • Provides adequate tissue for histopathology, immunohistochemistry, and molecular studies

2. Minimally invasive procedures (based on location)

   • EBUS-TBNA (Endobronchial ultrasound-guided transbronchial needle aspiration) for mediastinal nodes
   • EUS-FNA (Endoscopic ultrasound-guided fine needle aspiration) for posterior mediastinal nodes
   • CT-guided percutaneous biopsy for accessible nodes 1, 4

Laboratory Studies

• Complete blood count with differential
• Comprehensive metabolic panel
• Lactate dehydrogenase (LDH)
• Erythrocyte sedimentation rate (ESR)
• HIV testing
• PPD or interferon-gamma release assay for tuberculosis
• Specific serologies based on clinical suspicion 1

Disease-Specific Considerations

Suspected Malignancy

• Lymphoma: Flow cytometry, immunohistochemistry on biopsy specimens
• Lung cancer: Additional bronchoscopy, sputum cytology
• Head and neck cancer: Panendoscopy if clinically indicated 1

Suspected Infectious Etiology

• Tuberculosis: Acid-fast bacilli staining, culture, PCR
• Fungal infections: Fungal stains and cultures
• HIV-related: CD4 count, viral load, opportunistic infection workup 1, 5

Suspected Sarcoidosis

• Serum ACE levels
• Pulmonary function tests
• Bronchoalveolar lavage 5

Special Considerations

Location-Specific Approach

• Lower cervical nodes: Higher risk for malignancy, especially supraclavicular nodes (Virchow's node)
• Paratracheal and subcarinal nodes: Common in lung cancer, lymphoma, and granulomatous diseases
• Aortopulmonary window nodes: Often involved in left upper lobe lung tumors, requires specific assessment 1

Pitfalls to Avoid

1. Relying solely on imaging without tissue diagnosis
2. Performing fine-needle aspiration when excisional biopsy is needed for definitive diagnosis
3. Treating with antibiotics or corticosteroids before establishing diagnosis
4. Missing systemic diseases by focusing only on the enlarged nodes
5. Failing to consider non-malignant causes such as sarcoidosis, tuberculosis, and fungal infections 2, 5

Follow-up

• For unexplained lymphadenopathy with benign features, reassessment within 2-4 weeks
• For persistent lymphadenopathy despite negative initial workup, consider repeat imaging and biopsy
• For diagnosed conditions, follow-up based on specific disease protocols 2

Remember that mediastinal and lower cervical lymphadenopathy often represents serious underlying pathology, and a systematic approach to diagnosis is essential to guide appropriate treatment and improve patient outcomes.