Diagnosis of Pheochromocytoma

The goal of this study is to develop better methods of diagnosis and treatment for pheochromocytomas. These tumors, which usually arise from the adrenal glands, are often difficult to detect with current methods. Pheochromocytomas release chemicals called catecholamines, causing high blood pressure. Undetected, the tumors can lead to severe medical consequences, including stroke, heart attack and sudden death, in situations that would normally pose little or no risk, such as surgery, general anesthesia or childbirth.

Patients with pheochromocytoma may be eligible for this study. Candidates will be screened with a medical history and physical examination, electrocardiogram, and blood and urine tests. Study participants will undergo blood, urine, and imaging tests, described below, to detect pheochromocytoma. If a tumor is found, the patient will be offered surgery. If surgery is not feasible (for example, if there are multiple tumors that cannot be removed), evaluations will continue in follow-up visits. If the tumor cannot be found, the patient will be offered medical treatment and efforts to detect the tumor will continue. Diagnostic tests may include the following:

1. Blood tests - Two blood tests-glucagon stimulation and clonidine suppression-are done that require insertion of intravenous (i.v.) catheters (thin flexible tubes) into arm veins. While the patient rests lying down, a drug (glucagon or clonidine) is given through the i.v. line. Blood pressure and heart rate are monitored frequently, and blood is collected from the i.v. line to measure levels of catecholamines and their breakdown products, metanephrines.
2. Regional venous sampling - Selective vena caval sampling may be required for some patients. A catheter is placed into a large blood vessel called the inferior vena cava, through which blood circulating in the body returns to the heart. Blood samples are collected for measurement of catecholamines and metanephrines.
3. Standard imaging tests - Non-investigational imaging tests include computed tomography (CT), magnetic resonance imaging (MRI), sonography, and 131I-MIBG scanning. These scans may be done before and after surgical removal of pheochromocytoma.
4. PET imaging - Positron emission tomography (PET) scanning is done using an injection of a radioactive catecholamine called fluorodopamine. The fluorodopamine enters pheochromocytoma cells, making the tumor radioactive and visible on the PET scan. The scan takes up to about 2 hours.
5. Urine - A 24-hour urine collection is collected for analysis.
6. Genetic testing - A small blood sample is collected for DNA analysis.

PLEASE NOTE: Until further notice, we are not offering MIBG131 at this time.