#chestrad

The differential diagnosis of a middle mediastinal mass includes lymph nodes, foregut duplication cysts, tracheal/bronchial lesions, lipoma, esophageal lesions (benign or malignant) and vascular lesions (aortic aneurysm, varices).

This case is a 70-year-old man who presented with cough and hemoptysis. Chest radiograph reveals a right mediastinal mass that silhouettes the right hilar vessels, localizing the lesion to the middle mediastinum. There is also mass effect on the trachea and widening of the right paratracheal stripe. CT reveals a mass along the right tracheal border, which also encases the right mainstem bronchus. Biopsy revealed small cell bronchial carcinoma.

Can you spot the finding that gives this case away?

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Indistinct right heart border is right middle lobe pneumonia / right middle lobe collapse until proven otherwise. This is easily confirmed on the lateral view, where the finding is usually obvious. (lateral view posted in the comments).

Take a look at today's chest radiology case.

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There is rightward shift of the mediastinum, including the trachea, indicating volume loss in the right hemithorax. The right hemidiaphragm is obscured. These are the classic findings of right lower lobe collapse.

This week we will be showing a case series of chest radiographs. Take a minute to look at the image before you read on. Can you spot the problem?

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This case demonstrates a mass at the left hilum. In addition, the left hemidiaphragm is elevated, indicating volume loss, and there is air outlining the aortic arch and proximal descending aorta (the so-called "Luftsichel sign," or "air sickle" due to its shape). Findings are classic for left upper lobe collapse (in this case post-obstructive due to the mass). The hyperinflated superior segment of the left lower lobe is what creates the air sickle, as it is situated betwixt the collapsed lung and the aorta.

Today's #onlineresource is LearningRadiology.com. This is a great site for medical students and other non-radiologists, with lots of cases for beginners, as well as more advanced content for advanced readers. 

This chest radiograph shows bilateral paraspinal masses throughout the posterior mediastinum. In addition, there is medullary expansion of several posterior ribs (esp the left 4th and 5th ribs).  

The combination of rib expansion and paraspinal masses is essentially diagnostic of extramedullary hematopoiesis. Differential diagnosis includes hemoglobinopathies and myeloproliferative disorders. This patient had beta-thalassemia major. 

Here is today's case! If you have been paying attention this week, you should be able to immediately get this one!

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There is a right hilar mass with right upper lung opacity. The so-called Golden S sign or "reverse S sign" is seen in the right lung, classic for right upper lobe collapse. The hyperinflated right lower lobe forms the reverse S, due to the convex margin of the hilar mass.

What is your interpretation of today's case? ... ... ... ... ... It looks almost like the mirror image of yesterday's case. There is a left basal opacity and no retrocardiac vessels are seen through the heart shadow. This creates a "double left heart border." There is leftward shift of the mediastinum, including the trachea. Findings are classic for left lower lobe collapse, in this case caused by a left hilar mass. There is a small left pleural effusion.