Lu-177-DOTATATE (Lutathera) in Therapy of Inoperable Pheochromocytoma/ Paraganglioma

Background: Pheochromocytoma and paraganglioma are rare tumors. They usually form inside and near the adrenal gland or in the neck region. Not all these tumors can be removed with surgery, and there are no good treatments if the disease has spread. Researchers think a new drug may be able to help. Objective: To learn the safety and tolerability of Lu-177-DOTATATE. Also, to see if it improves the length of time it takes for the cancer to return. Eligibility: Adults who have an inoperable tumor of the study cancer that can be detected with Ga-68-DOTATATE PET/CT imaging Design: Participants will be screened with a medical history, physical exam, and blood tests. Eligible participants will be admitted to the NIH Clinical Center. Participants will get the study drug in an intravenous infusion. They will get 4 doses, given about 8 weeks apart. Between 4 and 24 hours after each study drug dose, participants will have scans taken. They will lie on their back on a scanner table. Participants will have vital signs taken. They will give blood and urine samples. During the study, participants will have other scans taken. Some scans will use a radioactive tracer. Participants will complete quality of life questionnaires. Participants will be contacted by phone 1-3 days after they leave the Clinical Center. They will then be followed every 3 to 6 months for 3 years or until their disease gets worse.