1 Clinical Instructor, Hospital Medicine, University of Colorado, 2 Assistant Professor of Medicine, University of Colorado, 3 Professor of Radiology, University of Washington
- Differentiate malignant metastases to the lung from primary lung cancer.
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.
Take Home Point
- Primary lung cancers tend to have ill-defined, spiculated margins
- 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.