Mediastinoscopy is a minimally invasive diagnostic procedure that involves the insertion of a mediastinoscope, a thin, flexible tube with a light and camera, through a small incision in the neck or chest to examine the mediastinum. The mediastinum is the central compartment of the thoracic cavity, containing vital structures such as the heart, major blood vessels, trachea, and esophagus. Mediastinoscopy is commonly used to diagnose and stage lung cancer, lymphoma, and other mediastinal abnormalities.