The Utility of the Ultrasonographic Characteristics in Differentiating Between Malignant and Tuberculous Mediastinal Lymphadenopathy During EBUS-TBNA.

Background: Ultrasonographic characteristics may help differentiate between benign and malignant lymph nodes during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). There is limited data on the utility of various ultrasonographic lymph node features to differentiate between malignant and tuberculous mediastinal lymphadenopathy.

Methods: We studied the various EBUS ultrasonographic lymph node characteristics (size, shape, margins, heterogeneous echotexture, calcification, central hilar structure, lymph node conglomeration, central intranodal vessel, and coagulation necrosis sign) from our available EBUS-TBNA database.

Results: We extracted 1086 subjects [547 with tuberculosis (TB) and 539 with malignant diagnosis]. Comparing the 2 groups (multivariate analysis), presence of central hilar structure (8.2% vs. 2.6%), coagulation necrosis sign (37.5% vs. 13.7%), lymph node conglomeration (30.5% vs. 7.2%), calcification (5.1% vs. 1.5%), and distinct margins (83.5% vs. 69.8%), were significantly more common in TB ( P <0.05). On the other hand, malignant lymph nodes were larger and more likely to show the presence of a central intranodal vessel (20% vs. 15.8%, P =0.04, multivariate analysis). The absence of lymph node conglomeration had the highest overall diagnostic accuracy (0.61) for the differentiation between malignant and tuberculous lymph nodes.

Conclusion: Sonographic lymph node characteristics may help differentiate malignant and tuberculous mediastinal lymphadenopathy. Contrary to previously published literature, we observed coagulation necrosis sign, heterogeneous echotexture and absent central intranodal vessel, more commonly in TB than malignant nodes. These findings from a TB endemic setting are different from other settings, where the prevalence of lung cancer is high in patients undergoing EBUS-TBNA.