pheochromocytoma. KEY INDEXING TERMS: Pheo-

ABSTRACT: Although rare, pheochromocytomas are po-tentially lethal tumors. Thus, it is important that physi-cians be able to diagnose these tumors. The definitive diagnosis of a pheochromocytoma rests on demonstrat-ing catecholamine overproduction. Once the diagnosis is established, computed tomography scan, magnetic resonance imaging, and metaiodobenzylguanidine stud-ies are utilized for localizing the tumor. This paper reviews the biochemical and radiologic studies useful for evaluating a patient for the possibility of