Inclusion Criteria

- INCLUSION CRITERIA:

Patients will have malignant pheochromocytoma defined as a locally-invasive adrenal tumor
and/or a metastatic extra-adrenal tumor located in tissues where chromaffin cells are not
normally present.

Histologic proof of pheochromocytoma is not required but the nature of the tumor will be
confirmed either by surgical pathological diagnosis or by biochemical measurements.

Patients may have single or multiple tumors. There must be at least one discrete
metastatic tumor that can be detected and measured by CT or MRI. Metastatic tumor sites
may or may not be resectable.

The tumor(s) must concentrate [131]I-MIBG.

Tumors may be stable, or be growing or increasing in number at the time of this study.
There will be no limit on tumor size.

Patients will be adults, male or female, and not be limited to any ethnic or racial
groups.

Patients will have a Karnofsky score of at least 60%.

Women of childbearing potential must practice an effective method of birth control while
participating in the study. All men must also practice an effective method of birth
control while in the study.

EXCLUSION CRITERIA:

Pregnant or lactating women will be excluded. A positive pregnancy test will exclude the
patient from further participation in this protocol.

Children (less than 18 years of age) and patients older than 70 years of age will be
excluded.

Patients will be further excluded if they have:

Impaired cardiovascular function (ejection fraction of less than 40%, symptomatic
congestive heart failure, sustained blood pressure over 190/100, angina pectoris);

Abnormal coagulation parameters (PT and PTT elevated by 30% above the normal);

Hematocrit below 30%, hemoglobin below 10 g/dl, white blood cell count below 3000 per
mm(3), absolute neutrophil count below 1000 per mm(3), platelet count below 100,000 per
mm(3));

Any reason not to accept blood transfusions which may be needed as treatment for
myelotoxicity from experimental [131I]-MIBG therapy;

Liver enzymes greater than 2.5 times the upper limit of normal; serum bilirubin greater
than 1.5 times the upper limit of normal.

Renal dysfunction (serum creatinine greater than 2.0 mg/dl);

Life expectancy less than 3 months;

Weight over 136 kg, This is the limit for the scanning tables;

Combined blood withdrawal greater than 450 ml during the six weeks preceding the study;

Impaired mental capacity that precludes written informed consent.

Prior experimental treatment with [131I]-MIBG, [90Y]-octreotide (an alternative agent
being investigated to treat pheochromocytoma), or chemotherapy will exclude the patient,
if this treatment was received in the previous 3 months provided the patient meets all
other entry criteria.

Labetalol, reserpine, calcium channel blockers, tricyclic anti-depressants, phenylephrine,
phenylpropanolamine, pseudoephedrine, ephedrine, and some atypical
anti-depressants/anti-psychotics interfere with uptake of [131I]-MIBG by
pheochromocytomas. If a patient cannot change to a non-interfering pharmaceutical, they
will be ineligible for the study.

Due to the potiential immunosuppressive effect of radiation therapy, patients with
positive HIV are excluded from this study. Patients with hepatitis B or hepatitis C are
excluded due to the potential of liver toxicity.

Patients who have received high dose chemotherapy with bone marrow transplant therapy or
stem cell infusion are excluded.

Patients who have received radiation therapy to the pelvis and/or spine are excluded.
Local radiation therapy to one site (excluding pelvis/spine) will be permitted provided
that at least 1 year has lapsed and the patient meets all other entry criteria.