Natural course of adrenal incidentalomas: Seven-year follow-up study

Most adrenal incidentalomas are nonfunctioning cortical adenomas that do no t require surgery. Operative treatment is indicated if the incidentaloma ha s malignant features as seen during the radiologic workup, is hormonally ac tive, or grows during follow-up. A conservative attitude is justified in as ymptomatic patients if we know that the natural course of these tumors is n ot disadvantageous. We followed a group of patients treated by observation to determine the natural course of adrenal incidentalomas, Altogether 30 in cidentalomas in 27 patients were detected in the Helsinki University Centra l Hospital from June 1981 through December 1992 and were re-examined during 1997. The patients were evaluated clinically, and hormonal testing was don e by performing a 1-mg overnight dexamethasone suppression test; the next d ay we measured the 24-hour urinary excretion of vanillylmandelic acid, meta nephrines and normetanephrines, and serum potassium. Magnetic resonance ima ging (MRI) was used to determine the size of the tumor. If the patient had died during the follow-up period, the causes of death from the death certif icates and autopsy reports were reviewed. The mean follow-up was 7 years. N ine patients had died, with none of deaths related to the incidentaloma. Si xteen patients were evaluated clinically and by the basic hormonal tests an d MRI; none showed any signs of hormonal activity or features of malignancy . Two patients did not want to be reexamined but stated that they were asym ptomatic. This follow-up study supports the conclusion that conservative th erapy is justified because the growth tendency of adrenal incidentalomas is slow and they seem to remain hormonally inactive.