Malignant Pleural Effusion – CXR

Table of Contents

Table of Contents

Published Oct 2020

Lauren Brown, MD1, Brandon Fainstad, MD2, David Godwin, MD3

1 Clinical Instructor, Hospital Medicine, University of Colorado, 2 Assistant Professor of Medicine, University of Colorado, 3 Professor of Radiology, University of Washington


  1. Use tracheal and mediastinal deviation to help differentiate the etiology of lung whiteout (opacification of hemithorax) and other large opacities.

Teaching Instructions

Plan to spend 5-10 minutes familiarizing yourself with the animations of the PowerPoint and the key findings of this chest X-ray.

Present the image either by expanding the window (bottom right) in a browser or downloading the PowerPoint file (recommended for optimal function).  Have the image pulled up in presenter mode before learners look at the screen to avoid revealing the diagnosis.  Ask a learner to provide an overall interpretation.  Then advance through the animations to prompt learners with key questions and reveal the findings, diagnosis, and teaching points.

Instructions: Ask a learner to provide an overall interpretation. Advance the slide for subsequent questions.

CXR Read: Opacification of right hemithorax (lung whiteout) with tracheal deviation away from the opacity. No notable opacities or effusion on the left.

Diagnosis: Malignant right sided pleural effusion from metastatic RCC.

Teaching: The differential for any large lung opacity is often narrowed by determining if it is a volume-occupying (mass) lesion by the deviation of the trachea, gastric bubble, and mediastinum away from the lesion versus volume losing (collapse) by deviation toward the lesion. This is particularly notable with the opacification of a hemithorax, as in this case. The differential of a volume-occupying opacification of a hemithorax is exclusively a large pleural effusion.

Differential based on change of structure positions:

Towards whiteout (volume loss)MidlineAway from whiteout (mass effect)

-Mainstem obstruction


-Pulmonary agenesis/hypoplasia


-Pleural mass

-Chest wall mass

-Pleural effusion

-Intra-pulmonary mass

-Diaphragmatic hernia

Refer to this post for another comparison of space-occupying versus space-losing lesions in the thorax.

Presentation Board

Take Home Point

  1. The differential for any large lung opacity is narrowed by determining if the mediastinum and trachea deviate away from (volume-occupying lesion) or toward (volume-losing lesion) the opacity.   


McLoud, Boiselle, & Boiselle, Phillip M. (2010). Thoracic radiology : The requisites (2nd ed., Requisites in radiology). Philadelphia: Mosby/Elsevier.

Brandon Fainstad


Comment on this article