Anterior mediastinal mass in the exam

Last revised by Andrew Murphy on 27 Jul 2022

Getting a film with an anterior mediastinal mass in the exam is one of the many exam set-pieces that can be prepared for.

The film goes up and after a couple of seconds pause, you need to start talking:

There is a left sided mediastinal mass that makes obtuse angles with the mediastinal contour.  The hilar vessels can be seen through the mass - this is the hilum overlay sign and means this is not in the middle mediastinum.  The paravertebral line can also be seen, placing this mass in the anterior mediastinum.

The differential includes lymphoma, thyroid malignancy, thymoma and teratoma and the age of the patient and accompanying clinical symptoms and signs would help order the list.

I would notify the referring clinician urgently and suggest a CT scan to assist diagnosis and assess the extent of disease.

Selected axial and sagittal slices from a contrast enhanced CT chest.

This confirms that the mass is in the anterior mediastinum.  There are fatty and calcific components suggesting a diagnosis of teratoma.  A CT-guided biopsy could be performed to confirm the diagnosis.

  • when the CT goes up - don't go back to the beginning. Use the phrase "this confirms..."
  • where there is fat and calcification in an anterior mediastinal mass, think teratoma
  • in lymphoma, Hodgkin's disease is more common in younger patients with lymphadenopathy isolated to the chest

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Cases and figures

  • Anterior mediastinal teratoma
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  • Anterior mediastinal teratoma
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  • Anterior mediastinal teratoma
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  • Hodgkin lymphoma - mediastinal
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