Mediastinoscopy is a surgical procedure to examine the mediastinum-the space behind the breast bone and infront of and between the lungs . Sometimes, people develop swellings in that area and there is a diagnostic dilemma-whether they have tuberculosis or cancers. When other investigations like PET-CT  scan or trans-oesophageal ultrasound guided biopsy cannot solve this, mediastinoscopy is performed.

During a mediastinoscopy, a small cut of about 2.5cm is made in the root of the neck just above the breast-bone. Then a endoscope (mediastinoscope) is inserted through the opening. A tissue sample can be collected through the mediastinoscope and then examined under a microscope for problems, such as infection, inflammation, or cancer.