Endocrine Abstracts

Introduction: Adrenal incidentalomas (AIs) are increasingly detected due to the widespread use of abdominal imaging for diagnostic purposes. AIs are usually benign non-functioning adenomas but few prospective studies exist regarding their evolution.

The aim of this study was to investigate the morphological and hormonal changes of AIs in a cohort of patients with long-term follow-up.

Materials and methods: This was a prospective observational study conducted at the department of Endocrinology in Hippokration General Hospital (Thessaloniki, Greece) from 2008. The following tests were performed: serum cortisol at 08:00 and 23:00, 24h-urinary free cortisol, 1-mg dexamethasone-suppression-test, plasma adrenocorticotrophic hormone (ACTH), serum aldosterone (ALDO), plasma renin activity (PRA), ALDO/PRA ratio and 24 h-urinary total metanephrines and catecholamines. Radiological assessment was repeated at 6–12 months and yearly thereafter.

Results: Forty patients (12 males and 28 females; mean age 58.9±11.6 years), with 51 AIs and follow-up of 19.8±18.3 months (range 0–48) were evaluated. The mean diameter was 27.5±11.5 mm, being unilateral in 29 [15 (37.5%) in the right and 14 (35%) in the left gland] and bilateral in 11 patients (27.5%). Two patients underwent adrenalectomy, revealing one benign cortical adenoma and one pheochromocytoma. Three patients (7.5%) had subclinical Cushing’s syndrome (SCS), 1 (2.5%) pheochromocytoma and 2 (5%) aldosteronoma. The remainder had non-secretory masses. One patient with SCS who underwent adrenalectomy experienced imrovement of dyslipidemia and normalization of blood pressure. Although 6 AIs were >40 mm, there were no malignancies detected.

Mass enlargement (5–10 mm) was observed in 6 AIs (15%) (from the first year of follow-up in 5), while mass shrinkage (27 mm) in 1 (2.5%). No hormonal evolution was noticed.

Conclusions: The vast majority of AIs involved benign, non-secretory lesions. Increase in size occurred early on follow-up and was more frequent than previously reported. Adrenalectomy led to amelioration of cardiovascular risk factors in SCS.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.