Adrenal incidentaloma: An important component of the clinical presentation spectrum of benign sporadic adrenal pheochromocytoma

Pheochromocytomas are rare tumors, and patients usually present with paroxysmal symptoms. However, because of the advances in and frequent use of computerized imaging, adrenal pheochromocytomas may be discovered incidentally in patients who lack typical signs and symptoms. To determine the prevalence of adrenal incidentaloma as the initial finding in patients with benign sporadic adrenal pheochromocytoma, we retrospectively reviewed the clinical findings of 150 patients with benign sporadic adrenal pheochromocytoma diagnosed at the Mayo Clinic, Rochester, Minnesota, from 1978 to 1995. Although the majority of patients had symptoms attributable to catecholamine excess, 15 (10%) presented with an adrenal mass lesion discovered serendipitously on radiologic examination in the absence of paroxysmal symptoms. Two of these patients were normotensive, and urinary excretion of metanephrines and catecholamines was normal in one. The other 13 patients presented with sustained hypertension and/or one of its complications as the sole manifestation of catecholamine excess, an excess confirmed by biochemical urinary studies. Adrenal incidentaloma represents part of the spectrum of presentation of benign sporadic adrenal pheochromocytoma, a presentation found in 10% of patients.