Epinephrine producing pheochromocytoma. Is the secretory pattern decisive for the clinical manifestation?

Adrenal incidentalomas are becoming a major clinical problem, due to increasingly frequent radiological examinations. We present two cases of patients referred to our department with a finding of an unsuspected adrenal mass. Both of them were normotensive and without symptomatology typical for pheochromocytoma. In one patient we found 20-times higher levels of epinephrine and 3-times higher levels of dopamine in 24-h urine, in the second patient there were 8-times higher levels of epinephrine alone. Norepinephrine in urine, as well as values of all adrenal cortical hormones were normal. The diagnosis of pheochromocytoma was confirmed in both cases by a 123I-metaiodobenzylguanidine (MIBG) scintigraphy. The patients underwent adrenalectomy, which was performed without complications. We conclude that levels of single catecholamines excreted are decisive for the clinical presentation of pheochromocytoma. Epinephrine producing pheochromocytoma is more often oligo- or asymptomatic. We stress the importance of a complete hormonal screening in every case of adrenal incidentaloma, with measuring levels of catecholamines and/or metanephrines.