The purpose of this research study is to find how active and safe 131 I-MIBG is in patients with resistant neuroblastoma, malignant pheochromocytoma and malignant paraganglioma.

Inclusion criteria for NB:

• Patients must have the diagnosis of NB in accordance with the International Criteria, i.e., either histopathology (confirmed by the MSKCC Department of Pathology) or BM involvement plus elevated urinary catecholamines.
• Must have a history of tumor progression or recurrence or failure to achieve complete response with standard therapy.
• Patients must have MIBG-avid NB and evaluable disease on MIBG scan at time of enrollment on protocol
• Prior Therapy: At least 2 weeks should have elapsed since any biologic therapy. Three weeks should have elapsed since last dose of chemotherapy.
• Age >1 year
• Determination that radiation safety restrictions during therapy period can be implemented.
• Stem cells: Patients for high does must have an autologous hematopoietic stem cell product cryopreserved and available for re-infusion after MIBG treatment. Patients for low dose do not require cryopreserved autologous hematopoietic stem cell product available. The minimum dose for peripheral blood stem cells is 2 X106 CD34+ cells/kg.
• Minimum life expectancy of eight weeks
• Signed informed consent indicating awareness of the investigational nature of this program.

Inclusion criteria for malignant CCT:

• Patients must have the diagnosis of malignant CCT i.e. malignant pheochromocytoma or malignant paraganglioma
• Patients must have MIBG-avid malignant CCT and evaluable disease on MIBG scan at time of enrollment on protocol
• Prior Therapy: At least 2 weeks should have elapsed since any biologic therapy. Three weeks should have elapsed since last dose of chemotherapy.
• Age between 1 and 21 years and able to cooperate with radiation safety restrictions during therapy period
• Stem cells: Patients must have an autologous hematopoietic stem cell product cryopreserved and available for re-infusion after MIBG treatment. The minimum dose for peripheral blood stem cells is 2 X106 CD34+ cells/kg.
• Minimum life expectancy of eight weeks.
• Signed informed consent indicating awareness of the investigational nature of this program.

Exclusion Criteria:

• Severe major organ toxicity. Specifically, renal, cardiac, hepatic, pulmonary, gastrointestinal and neurologic toxicity should all be grade 2 or less. A grade 3 hearing deficit is acceptable.
• Active serious infections not controlled by antibiotics.
• Pregnant women are excluded for fear of danger to the fetus. Therefore negative pregnancy test is required for all women of child-bearing age, and appropriate contraception is used during the study period.
• Inability or unwillingness to comply with radiation safety procedures or protocol requirements.