A simplified diagnostic approach to pheochromocytoma. A review of the literature and report of one institution's experience. Pheochromocytoma is an unusual but potentially devastating tumor. Although a high index of suspicion is necessary, the likelihood of a pheochromocytoma is lower in the absence of the typical symptoms and findings. Nonetheless, screening must be broadened to include patients with a lower risk of the disease, such as those with resistant or labile hypertension who are minimally symptomatic. Extensive diagnostic evaluations should be reserved for those whose clinical or laboratory findings are more suggestive. Symptoms in a group of patients in whom a pheochromocytoma was seriously considered but excluded overlap symptoms in patients with a pheochromocytoma. Certain symptoms are useful: flushing to suggest a non-pheochromocytoma illness; visual symptoms, flank pain, and pallor to suggest that a pheochromocytoma is more likely. Combinations of symptoms can be of value: 2 or more symptoms from the triad of headache, palpitations, and diaphoresis were present in the majority of pheochromocytoma patients, but in a smaller number of non-pheochromocytoma patients. The presence of the entire triad is more specific, but less sensitive. New hypertension, or hypertension associated with unexplained orthostatic hypotension, are suggestive of an underlying pheochromocytoma. Twenty-four-hour urine studies are consistently abnormal in patients with a pheochromocytoma, but are also elevated in a significant proportion of non-pheochromocytoma patients. Values greater then 1.5-2-fold above the upper limit of normal are very suggestive that a pheochromocytoma is present, and warrant a more intensive subsequent evaluation. Imaging studies are reliable in the diagnosis of pheochromocytoma, and can help to confirm or exclude the disease. Patients with a higher clinical likelihood and any elevated urinary testing, or with a lower clinical likelihood and persistently and/or significantly elevated urinary testing, should have imaging studies performed. This combination of clinical screening, 24-hour urinary testing, and imaging studies is a useful and reliable approach to patients suspected of harboring a pheochromocytoma. 