ADRENAL INCIDENTALOMA - AN OVERVIEW OF HORMONAL DATA FROM THE NATIONAL ITALIAN STUDY-GROUP

Adrenal masses are more and more frequently detected by adrenal ultras ound, computed tomography or nuclear magnetic resonance carried out fo r a reason other than the suspicion of adrenal disease (incidentalomas ). The finding of an incidentaloma still leaves many diagnostic and th erapeutic questions open. We report the results of a multicentric retr ospective evaluation of patients with adrenal incidentalomas, performe d by a Study Group of the Italian Society of Endocrinology According t o the definition of incidentaloma. exclusion criteria a priori were: s evere or paroxysmal hypertension, frank hypokalemia and clinical signs of hypercortisolism or hyperandrogenism. 29 centers participated in t he study and the data obtained by questionnaire were collected in 2 ce nters for final elaboration. Center 1 carried out the epidemiological and clinical evaluation. Basal and dynamic hormonal evaluation of 786 among the 1013 cases recruited were performed in our center (center 2) . Functional studies included: diurnal rhythm of cortisol, urinary fre e cortisol (UFC), ACTH, DHEAS, 17-OH progesterone, testosterone, andro stenedione, supine and upright plasma renin activity (PRA) and aldoste rone, urinary aldosterone, urinary catecholamines and VMA. The hormona l dynamic evaluation included the overnight dexamethasone suppression test (1 mg), CRH test and ACTH test. In our study, 89% (702 patients) of adrenal incidentalomas were non-hypersecretory masses; 6.2% (49 pat ients) showed a preclinical Gushing's syndrome (PCS) (at least two alt ered parameters of pituitary-adrenal axis); 3.4% (27 patients) were ph eochromocytomas; 0.89% (7 patients) were aldosteronomas. One tumor was a masculinizing adrenocortical carcinoma. Two hundred sixty patients underwent surgical exploration and the histological diagnosis showed: 138 adenomas (53%), 32 carcinomas (12%), 26 pheochromocytomas (10%), 1 6 myelolipomas (8%), 13 cystic lesions (5.5%), 7 tumors of neuronal li neage (3%), 12 metastases (49%), 13 others (5%). The 138 patients with adenomas had the following hormonal diagnosis: 103 nonfunctional aden omas (74%), 31 PCS (23%) and 4 cases of hyperaldosteronism (3%). In th e patients with PCS an abnormal dexamethasone suppression test was fou nd in 86% of cases (37/41 patients). Values for ACTH were low in 78% ( 32/41 patients). UFC was elevated in 64% of patients, the diurnal rhyt hm of cortisol evaluated in 14 patients was absent in 7. Only in 50% o f cases DHEAS values (12/24 patients) were decreased, whereas they wer e normal in the other 50%. Interestingly, 8 patients with normal DHEAS and normal UFC showed nonsuppressible cortisol by dexamethasone test (1 mg). Blunted ACTH response to CRH was detected in 9 of 14 patients (64%). Thus our data suggest that the best parameter for evaluating su bclinical hypercortisolism seems to be the overnight dexamethasone sup pression test. In 27 patients with pheochromocytoma 24-hour urinary ca techolamine and VMA levels were elevated in 86 and 46% of cases respec tively. In 7 patients with hyperaldosteronism upright PRA was suppress ed in 100% of cases and aldosterone plasma levels were elevated in 6 p atients (86%); serum potassium level was slightly decreased in 60% of cases. In 86 of 138 histologically proven adenomas, DHEAS levels were: normal in 59% of patients, decreased in 36% and elevated in 4.6%, whe reas in 22 of 32 cortical carcinomas evaluated, DHEAS levels were norm al in 63% of cases, decreased in 18% and elevated 18%. Post-ACTH 17-OH progesterone levels were elevated in 52% (62/118 patients) of non-fun ctioning adenomas and in 7 of 4 carcinomas. Not enough data are yet av ailable postoperatively, In summary, endocrine evaluation can lead to the identification of a nonnegligible number of cases of clinically un suspected pheochromocytomas and subtle hypercortisolism (about 3.4 and 6.2%, respectively of all adrenal incidentalomas), while cases of pri mary subclinical aldosteronism are rarely found, Most of the clinicall y silent carcinomas showed no major hormonal abnormalities, except for an increased DHEAS in 18% of cases. These data suggest that a series of selected biochemical tests should be performed in all incidentally discovered adrenal masses. This would include 24-hour urinary catechol amine, plasma cortisol postsuppression with dexamethasone 1 mg, uprigh t PRA and DHEAS. The role of stimulated 17-OH progesterone in identify ing the few patients with adrenal masses due to 21-hydroxylase deficie ncy remains to be evaluated.