Bronchial Anthracofibrosis and Macroscopic Tissue Pigmentation on EBUS-TBNA Predict a Low Probability of Metastatic Lymphadenopathy in Korean Lung Cancer Patients

The identification of mediastinal lymph nodes (LNs) in lung cancer is an important step of treatment decision and prognosis prediction. The endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is widely used to assess the mediastinal LNs and tissue confirmation in lung cancer. As use of bronchoscopy or EBUS-TBNA has been increased, bronchial anthracofibrosis (BAF) has been detected frequently. Moreover, BAF is often accompanied by mediastinal lymphadenopathy and showed false-positive positron emission tomography uptake, which mimics metastatic lymphadenopathy in lung cancer patients. However, clinical implication of BAF during bronchoscopy is not well understood in lung cancer. We retrospectively reviewed 536 lung cancer patients who performed EBUS-TBNA and observed BAF in 55 patients. A total of 790 LNs were analyzed and macroscopic tissue pigmentation was observed in 228 patients. The adjusted odds ratio for predicting malignant LN was 0.46 for BAF, and 0.22 for macroscopic tissue pigmentation. The specificity of BAF and macroscopic tissue pigmentation for predicting a malignant LN was 75.7% and 42.2%, respectively, which was higher than the specificity of using LN size or standard uptake value on PET. In conclusion, BAF and macroscopic tissue pigmentation during EBUS-TBNA are less commonly found in malignant LNs than reactive LNs in Korean lung cancer patients.