Purpose: Cushing’s syndrome is caused sometimes by ectopic ACTH secretion. Finding the exact location of the tumor making extra ACTH is necessary for successful surgical treatment.

In 10% to 20% of patients, Cushing’s Syndrome is caused by ectopic production of the hormone ACTH. Often the ectopic ACTH is produced by a tumor of the lung, thymus, or pancreas. However, in approximately 50% of patients the tumor cannot be found even with the use of extensive imaging studies such as CT, MRI, and nuclear scans (111-indium pentetreotide). Positron emission tomography (PET scan) using DOPA has the ability to detect pathologic tissue based on physiologic and biochemical processes within the abnormal tissue.

Participating patients will be admitted to the Clinical Center at the National Institutes of Health and will receive a standard evaluation of Cushing syndrome and its cause. These tests include MRI of the pituitary, blood, saliva and urine tests, CRH stimulation and dexamethasone suppression test, and inferior petrosal sinus sampling (IPSS). Most of these tests will be done on our inpatient unit or in our day hospital. If the testing indicates a pituitary tumor making ACTH, patients will be offered surgery at the NIH. If the testing indicates ectopic ACTH secretion, we will perform standard studies to look for the tumor, as well as two research studies, F-DOPA PET and 3T MRI. The 3T MRI has a stronger magnet than the more common scanners and might give a better picture. Imaging studies of the neck, chest, abdomen and/or pelvis, as indicated by the history, physical examination and biochemical tests will be done by Octreoscan, CT and/or MRI scans. If the standard imaging studies identify a clear-cut tumor, we will consider surgical exploration, usually at a later admission. If only the research studies are positive, we will not do surgery but will continue to follow with imaging at 6-12 month intervals, and treat the Cushing syndrome with medication or adrenalectomy as needed.

Criteria for admission into the study:

• Age 18-70 years
• Cushing’s syndrome caused by ACTH secretion confirmed biochemically
• No severe heart, liver, or kidney disease or severe active infection
• No known allergy to [111In-DTPA-D-Phe]-pentetreotide or other somatostatin analogues or x-ray dye
• Body weight less than 136 kg

There is no charge for admission and testing at the NIH. For more information or subject referrals contact:

Lynnette Nieman, M.D.
NICHD/National Institutes of Health
Building 10, CRC, 1 East, Rm 1-3140
10 Center Dr, MSC 1109
Bethesda MD 20892-1109
Fax: 301-402-0884
email: [email protected]