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Introduction

Pheochromocytomas are rare tumors that typically arise from the adrenal gland. Similar tumors may develop outside the adrenal gland and are called extra-adrenal paragangliomas. These tumors often release catecholamines (e.g., norepinephrine and epinephrine), resulting in hypertension and other common clinical features such as headache, palpitations and increased sweating. The main therapy is surgical resection of the tumor.

If a pheochromocytoma or paraganglioma is undetected, stimuli that normally would not pose a hazard, such as surgery, childbirth, or general anesthesia, can evoke catecholamine secretion by the tumor, with clinically significant and even catastrophic outcomes. The diagnosis of pheochromocytoma and its localization can be challenging, because measurements of plasma levels or urinary excretion of catecholamines and their metabolites and radio-iodinated metaiodobenzylguanidine (MIBG) scanning can yield false-negative results in patients harboring the tumor. Computed tomographic and magnetic resonance imaging lack sufficient specificity. The molecular mechanisms by which genotypic changes predispose to development of pheochromocytoma remain unknown, even in patients with identified mutations. Moreover, pheochromocytomas in patients with hereditary predispositions differ in terms of their growth, malignant potential, catecholamine phenotype, and responses to standard screening tests such as glucagon stimulation and clonidine suppression tests. This protocol focuses on molecular and genetic studies that elucidate the bases for predisposition to develop pheochromocytomas and for expression of different neurochemical phenotypes and malignant potentials, new imaging approaches, based on 6-[18F]fluorodopamine ([18F]-6F-DA) and [18F]-L-3,4-dihydroxyphenylalanine [18F]-(DOPA) positron emission tomographic (PET) scanning, and new biochemical diagnostic criteria, based on measurement of plasma metanephrines.

For patients who have an appointment at the NIH:

  • Navigate through all items of the menu on your left to learn more about the investigations, and to find essential instructions for preparing for your NIH visit as well as the study protocol consent form. In addition, we ask you to fill out the questionnaires regarding your personal clinical information (under the menu 'Questionnaires').

Please contact us if you have any questions or concerns.