Approach to the diagnosis and staging of mediastinal masses.

Improvements in cytologic techniques have made needle biopsy much more helpful in diagnosing mediastinal masses. We have added thoracoscopy to the surgical armamentarium. Tumor markers facilitate accurate diagnosis. In the field of imaging, cysts can now be identified almost certainly and aspirated. Magnetic resonance imaging has changed the workup of patients with posterior mediastinal masses. Staging investigations should be based on the type of tumor and the likelihood of spread.