Can a bronchoscopy sample mediastinal lymph nodes?

Bronchoscopy for Sampling Mediastinal Lymph Nodes

Yes, bronchoscopy with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) can effectively sample mediastinal lymph nodes and is the recommended first-line minimally invasive procedure for mediastinal nodal staging in lung cancer.

Capabilities of EBUS-TBNA for Mediastinal Lymph Node Sampling

EBUS-TBNA can access and sample specific mediastinal lymph node stations:

• Accessible lymph node stations via EBUS-TBNA 1:

  • Paratracheal lymph nodes (stations 2L, 2R, 4L, 4R)
  • Subcarinal lymph nodes (station 7)
  • Hilar lymph nodes (station 10)
  • Intrapulmonary lymph nodes (stations 11-12)

• Limitations: Not all mediastinal lymph node stations can be reached by EBUS-TBNA alone. Stations 5 and 6 (aortopulmonary window) are generally not accessible via EBUS-TBNA 1.

Combined Endosonography Approach

For complete mediastinal staging, a combined approach is often recommended:

• EBUS-TBNA + EUS-FNA: Combining endobronchial ultrasound with endoscopic ultrasound-guided fine needle aspiration provides access to virtually all mediastinal nodal stations 1.

• Single-scope technique: Both procedures can be performed using a single endobronchial ultrasound bronchoscope in one session by one operator 2.

• Complementary coverage:

  • EBUS-TBNA: Best for paratracheal, subcarinal, and hilar nodes
  • EUS-FNA: Better access to stations 2L, 4L, 7,8,9, and structures below the diaphragm 1

Diagnostic Performance

• High diagnostic yield: Combined endosonography approach has a sensitivity of 96% and negative predictive value of 95% for mediastinal staging 2.

• Individual performance:

  • EBUS-TBNA alone: 92% sensitivity 2
  • EUS-FNA alone: 89% sensitivity 2
  • Conventional TBNA: 61-65% sensitivity 3

Recommended Sampling Approach

For optimal mediastinal staging in lung cancer patients:

• Sample at least three different mediastinal nodal stations (4R, 4L, 7) for complete assessment 1.

• Target all abnormal lymph nodes identified by size (>10mm) or FDG avidity on PET 1.

• Consider combined EBUS-TBNA and EUS-(B)-FNA for more complete mediastinal staging in a single session 1.

Clinical Applications Beyond Lung Cancer Staging

• Diagnosis of mediastinal masses: EBUS-TBNA can be used for diagnostic purposes in patients with centrally located lung tumors adjacent to larger airways 1.

• Tuberculosis diagnosis: EBUS-TBNA is recommended for diagnosis in patients with suspected TB with mediastinal and/or hilar adenopathy requiring lymph node sampling 1.

• Lymphoma diagnosis: While EBUS-TBNA can be used for lymphoma diagnosis, its diagnostic yield is variable (68.7% pooled accuracy) and may be limited by the need for larger tissue samples and architectural assessment 1.

Potential Pitfalls

• Limited tissue samples: Standard EBUS-TBNA provides cytologic specimens, which may be insufficient for certain diagnoses like lymphoma that require assessment of tissue architecture 1, 4.

• Incomplete sampling: Failure to sample at least three different nodal stations may result in incomplete staging 1.

• Need for surgical sampling: Some lymph node stations (particularly stations 5 and 6) may still require surgical approaches like video-assisted thoracic surgery 1.

Bronchoscopy with EBUS-TBNA represents a minimally invasive, safe, and effective approach for sampling mediastinal lymph nodes, with significant advantages over more invasive surgical procedures for initial mediastinal staging.