Mediastinoscopy is surgery to look at the inside of the upper chest between and in front of the lungs. This area is called the mediastinum.

During the test, a doctor makes a small cut (incision) in the neck just above the breastbone or on the left side of the chest next to the breastbone. Then the doctor places a thin scope in the opening. A tissue sample (biopsy) can be collected through the scope and then looked at under a microscope for lung problems. These problems might include infection, inflammation, or cancer.

In many cases, this surgery has been replaced by other biopsy methods that use computed tomography (CT),endoscopic ultrasound, or bronchoscopy to guide a biopsy needle. This test may still be needed when the other methods can’t be used or when they don’t show clear results.