Get yourself another PCP. Any mass or node that you describe as growing in size to the point where it inhibits normal functions could very easily be a mediastinal cyst. There are two tests available to detect these abnormal cysts - a blood test (CBC) and a CT or CAT scan. Some cysts just refuse to show up on an xray because of their composition or makeup. Most mediastinal are benign but can push against vital organs and that's what makes them a priority to identify and treat.
