Endocrine Abstracts

Background: Resource-saving and medically safe investigations of adrenal incidentaloma (AI) is one of the challenges in modern endocrinology. The absolutely majority of AIs are benign and hormonally inactive. Mild hypercortisolemia is the most common finding in hormonally active AI and is often referred to as subclinical Cushing syndrome (SCS). SCS is associated with increased risk of type 2 diabetes, poorly regulated hypertension, osteoporosis and cardiovascular disease. There is a lack of a generally accepted definition of SCS. An overnight 1 mg dexamethasone test (DST) is usually used to diagnose SCS but S-DHEAS measurement has recently been suggested as an alternative diagnostic method. The aim of this study was to investigate the prevalence of SCS and if S-DHEAS could be used to identify SCS.

Methods: In this prospective study of all AI diagnosed in a defined area we used the ESE definitions of mild hypercortisolemia, i.e., autonomous cortisol secretion (ACS) and possible autonomous cortisol secretion (PACS). A serum cortisol ≤50 nmol/l after DST excludes ACS. Serum cortisol 51–138 nmol/l after DST is defined as PACS and serum cortisol >138 nmol/ l as ACS if overt Cushing syndrome has been excluded. S-DHEAS was analyzed in all individuals to investigate a possible correlation with subnormal level of DHEAS and ACS/PACS.

Results: 98 individuals with AI were investigated with DST and S-DHEAS. The mean age was 67.5 (38–86) years and 42 (43%) were males. PACS or ACS were found in 37 (38%, PACS n=30, ACS n=7). Subnormal S-DHEAS was found in 8 (22%) patients with PACS, 2 (29%) with ACS and 4 (7%) patients with normal DST.

Conclusion: Mild excessive cortisol secretion is common in AI. However, using the ESE definition only 7% had ACS which may be slightly lower prevalence than previous studies using other definitions for SCS. DHEAS could not replace DST.