 The purpose of this trial is to test the use of AZEDRA as a treatment for pheochromocytoma and paraganglioma, a rare disease. This Phase II study will help determine primarily if using the drug reduces the amount of blood pressure medication being taken as a result of the cancer and secondarily to determine such things as the effectiveness of the study drug in treating the cancer, additional safety measures, and to assess if the drug helps the quality of life and use of pain medication. All subjects will receive an imaging dose with scans followed by two therapeutic doses given approximately 3 months apart. 