Endocrine Abstracts

Increased use and improved technology of imaging procedures have led to increased recognition of adrenal incidentalomas. The aim of this study is to evaluate the natural course of benign adrenal tumours in terms of tumour growth and hormone secretion.

Subjects referred between 2001 and 2008 for the evaluation of adrenal tumours were included. Computed tomography (CT) was the initial radiological intervention. Initial hormonal evaluation included 1 mg or 2 day 2 mg dexamethasone suppression test, urinary free cortisol (UFC), 08.00 a.m. ACTH and DHEAS levels. In subjects with elevated post DST cortisol (>1.8 mcg/dl), elevated UFC (>110 mcg/day), and suppressed ACTH and DHEAS levels, midnight cortisol was evaluated (normal<7.5 mcg/dl). Urinary catecholamine excretion and aldosterone/renin ratio were also measured.

Three hundred and two consecutive subjects with adrenal tumours were included. Fifty-six patients had adrenalectomy because of hyperfunctioning tumours or malignant appearance on radiological interventions. Among the remaining 246 subjects, 132 participants were selected with appropriate radiological and hormonal follow up data. Mean age was: 55 years and female dominance was present (99/33). There were 98 subjects with non-functioning adenomas, 26 subjects with subclinical cushing syndrome, 5 subjects with myelolipomas and 3 subjects with primary hyperaldosteronism. Median follow up duration was 23.5 months. In 7 (5.3%) subjects, a decrease in tumour size was observed, while an increase was observed in 23 (17.4% participants). In 97 subjects with non-functioning adenomas, 3 (3.08%) patients developed subclinical cushing syndrome while pheochromocytoma or primary hyperaldosteronism were not diagnosed during follow up. Median follow up was significantly higher in subjects with tumour size increase (21 vs 32.5 months, P<0.05).

This prospective study demonstrates that malignancy and tumour hypersecretion do not frequently develop during short term follow up in subjects with benign adrenal tumours. Increase of tumour size is not rare and may be detected in patients with relatively longer follow up durations.