Endobronchial ultrasound (EBUS) characteristics of benign and malignant mediastinal lymph nodes

Abstract

Introduction: Mediastinal lymph nodes enlargement is a frequent diagnostic challenge for which EBUS and transbronchial needle aspiration (TBNA) are used for diagnosis. EBUS differences between malignant and benign nodes characteristics could help in the diagnosis but have not been defined. Aim: To define possible characteristics that might differentiate benign and malignant lymph nodes by EBUS. Methods: 67 patients who underwent EBUS-TBNA, for diagnosis of enlarged mediastinal lymph nodes were studied. Lymph node EBUS features, including size (short axis >1 cm), shape (oval, round), ecogenecity (homogeneous-heterogeneous), margin (distinct-indistinct), presence of central hilar structure and coagulation necrosis sign were recorded. Results: 50 of the 67 lymph nodes had a pathological diagnosis of malignancy and 17 were benign. Malignant lymph nodes had short axis >1cm (68% vs 23%, p=0.002), distinct margin (68% vs 29%, p=0.009), central hilar structure (78% vs 47%, p=0.03) and heterogeneous ecogenecity (88% vs 23%, p=0.05) when compared to benign nodes. Shape was not different, while coagulation necrosis had a tendency to be increased in malignancy (58% vs 12%, p=0.09). The features of malignancy were similar in lymph nodes involved in primary lung cancer or other organs’ tumors. Conclusions: A short axis >1cm, heterogeneity, a well defined margin and the presence of a central hilar structure are features of malignancy in lymph nodes. Evaluation by EBUS can be helpful to differentiate malignant from benign nodes during the diagnostic procedure.