Mediastinal lymph node staging by EBUS-TBNA and CT: Characteristics of lymph node enlargement caused by anthracosis and other benign conditions

Objectives: Aim of this comparative study was to assess the accuracy of computed tomography (CT) and endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) for mediastinal lymph node staging in cases of lymph node enlargement due to anthracosis and other benign conditions. Methods: In a retrospective analysis we report on the MSCT findings of 39 patients (28 males, 11 females) with EBUS-TBNA confirmed diagnosis of 53 enlarged lymph nodes due to anthracosis. A control group comprised 20 consecutive patients with 27 enlarged lymph nodes (11 males, 9 females) due to chronic lymphadenopathy (n = 14) or sarcoidosis (n = 13). Results: No significant differences were observed between the two groups regarding size (mean short axis diameter 13.7mm vs. 14.5mm), shape (most often oval) or presence of lymph node confluence (32.1% vs. 33.3%), contrast enhancement (3.8% vs. 3.7%), and fatty involution (3.8% vs. 3.7%). In comparison with the control group anthracotic lymph nodes were significantly less often ill-defined in EBUS (5.7 vs. 25.9, p = 0.025) as well as in CT (1.9% vs. 18.5%, p = 0.01), but more often showed calcifications in CT (24.5% vs. 3.7%, p = 0.017). Lymph node colliquation was seen neither in anthracosis nor in other benign conditions. Conclusions: Mediastinal lymph node enlargement due to anthracosis, lymphadenopathy and sarcoidosis show some different findings in EBUS and CT but cannot definitely be differentiated. Advances in knowledge: Radiologists should be aware of mediastinal lymph node enlargement due to anthracosis.