Sarcoidal reactions in regional lymph nodes of patients with non-small cell lung cancer: incidence and implications for minimally invasive staging with endobronchial ultrasound.

BACKGROUND: Both malignancy and granulomatous diseases may be diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Sarcoidal reactions may be seen in the presence of non-small cell lung cancer (NSCLC). Demonstration of granulomas by lymph node EBUS-TBNA in the staging of NSCLC is of uncertain significance. AIMS: To determine the frequency of sarcoidal reactions in lymph nodes of patients with NSCLC. To report the frequency of co-involvement of sarcoidal reactions with metastatic NSCLC in regional lymph nodes.
METHODS: We prospectively examined 50 consecutive patients undergoing EBUS-TBNA for staging of suspected or confirmed NSCLC. We also performed a retrospective chart review of 187 patients undergoing lobectomy or mediastinoscopy for NSCLC.
RESULTS: EBUS-TBNA revealed non-necrotising granulomas in one patient, and in 45 patients it revealed metastatic primary lung malignancy. Surgical lymph node sampling was performed in 187 patients undergoing treatment for, or staging of, NSCLC. Sarcoidal reactions were seen in regional lymph nodes of eight (4.3%) of patients, with all lymph nodes free of metastatic NSCLC (pathologic Stage I) (p=0.02). Four of these patients were pre-operatively assessed as Stage III (cN2/3). None had a prior history of sarcoidosis or other granulomatous diseases. All eight patients remain alive and recurrence-free.
CONCLUSIONS: Sarcoidal reactions are seen in 4.3% of all patients with NSCLC. Metastatic involvement by NSCLC is not seen in lymph nodes exhibiting sarcoidal granulomatous reactions. Non-necrotising granulomas revealed by EBUS-TBNA of lymph nodes during staging of NSCLC should serve to indicate the absence of lymph node metastases.