Lung Metastases, “Cannonball Lesions” – CXR

Table of Contents

Table of Contents

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. Differentiate malignant metastases to the lung from primary lung cancer.

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.

CXR Interpretation: Numerous bilateral basilar predominant, well-defined pulmonary nodules, with large right pleural effusion concerning for metastases.

Diagnosis: Diffusely metastatic neuroendocrine tumor from an unknown primary.

Teaching: Lung metastases are typically are well-defined, distributed toward the bases, and the periphery reflecting hematogenous spread. There is also probably right-sided pleural metastasis based on the effusion. Primary lung cancer nodules tend to have ill-defined spiculated margins and are often located centrally or apically.

Presentation Board

Take Home Point

  1. Primary lung cancers tend to have ill-definedspiculated margins
  2. Metastases to the lung characteristically have a “cannonball” appearance with well-defined borders and are distributed bilaterally toward the bases and periphery of the lung reflecting hematogenous spread.


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

Brandon Fainstad


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