ABNORMALITIES OF ENDOCRINE FUNCTION IN PATIENTS WITH CLINICALLY SILENT ADRENAL MASSES

Because, in recent years, patients with incidentally discovered adrena l masses have been encountered increasingly, their endocrine function was investigated in basal conditions and after dynamic tests. Thirty-t wo patients (23 women and 9 men, aged 28-74 years) were studied. Lesio n diameter, as documented by computed tomography and/or nuclear magnet ic resonance imaging, ranged between 5 and 65 mm; the tumors were loca lized on the right in 22 patients, on the left in 5 and bilaterally in 5 cases. In basal conditions, urinary free cortisol (UFC) excretion, plasma adrenocorticotropin (ACTH) and cortisol levels were normal, exc ept for 4 patients who showed high UFC and ACTH levels in the low-norm al range. Ovine corticotropin-releasing hormone (CRH, 1 mu g/kg iv) wa s given to 18 patients, inducing normal ACTH and cortisol responses in 12, blunted responses in 4 and no response in 2 cases. No reduction i n ACTH and cortisol levels after suppression tests was observed in 4 o f 29 patients after dexamethasone (1 mg overnight) or in 6 of 29 after loperamide. The 4 patients who were unresponsive to both tests did no t show any further inhibition after high-dose dexamethasone administra tion, had low plasma ACTH levers and showed impaired or absent respons es to the CRH test: they were diagnosed as affected with preclinical G ushing's syndrome. An exogenous ACTH test performed in 30 patients cau sed a normal cortisol rise. Basal mean 17-hydroxyprogesterone (17-OHP) levels were not different from those in normal subjects. After ACTH t he 17-OHP rate increase was higher than in normal subjects (17-OHP(30- 0/30 min))/30min = 0.31 +/- 0.04 VS 0.07 +/- 0.01 nmol . I-1 . min-1; mean +/- SEM, p < 0.01); in particular, this parameter was elevated in Is of 30 patients (17-OHP(30-0/30 min) range = 0.23-1.07 vs 0.01-0.19 nmol . I-1 . min-1 in normal subjects). In a subset of 11 patients, s erum markers of bone (bone-GLA protein (BGP) and carboxyterminal cross -linked telopeptide of type I collagen (ICTP)) and collagen turnover ( aminoterminal propeptide of type III procollagen (PIIINP)) were signif icantly (p < 0.01) lower than in normal subjects: in particular, in 2 preclinical Gushing's patients they were markedly reduced and rose aft er unilateral adrenalectomy. Of these 2 patients who underwent surgery , 1 showed a secondary hypoadrenalism. The histological study in 7 ope rated patients revealed the presence of benign adenoma in 4 cases and carcinoma, myelolipoma and hematoma in the others. In conclusion, in p atients with incidentalomas endocrine testing is recommended because a bout two-thirds of them show subtle signs of adrenal overactivity. In patients with enzymatic defects of steroidogenesis a surgical approach is not suggested. On the contrary, the existence of a preclinical Gus hing's syndrome has to be investigated carefully and followed up in or der to disclose the possible appearance of clinical and/or metabolic f eatures induced by the hypercortisolism and to suggest a surgical trea tment.