Mediastinal mass: CXR

When interpreting masses on a CXR, it can sometimes be very difficult to discern whether a mass originates in the lung or in the mediastinum. There are a few ways that can greatly help to localize masses to the mediastinum including the following: 1. Mediastinal masses will not contain air bronchograms; and, 2. Mediastinal mass margins with the lung will be obtuse, rather than acute (see Image 1). Common mediastinal masses include lymphadenopathy and thymomas. Mediastinal masses are important for the Anesthesiologists to consider and recognize because they can cause obstruction of the tracheobronchial tree and obstruction of the pulmonary artery and superior vena cava.

Image 1: Demonstration of how lung masses create acute angles with the lung whereas mediastinal masses create obtuse angles with the lung. Image Source: Authors: Sanjeev Bhalla, Marieke Hazewinkel and Robin Smithuis, RadiologyAssistant.nl

Image 2: On the left is a lung mass with acute angle margins with the lung and on the right is an anterior mediastinal mass with obtuse angles with the lung parenchyma. Image Source: Authors: Sanjeev Bhalla, Marieke Hazewinkel and Robin Smithuis, RadiologyAssistant.nl