High prevalence of subclinical hypercortisolism in patients with bilateral adrenal incidentalomas: a challenge to management.

OBJECTIVE

The prevalence of subclinical hypercortisolism (SH) in unilateral incidentalomas (UI) has been extensively studied; however, patients with bilateral incidentalomas (BI) have not been thoroughly investigated. We therefore aimed to describe the characteristics of patients with BI compared to their unilateral counterparts. The surgical outcome in a small number of patients is reported.

DESIGN

Observational retrospective study in a single secondary/tertiary centre.

PATIENTS

One hundred and seventy-two patients with adrenal incidentalomas (41 with BI).

MEASUREMENTS

Morning cortisol (F), ACTH, dehydroepiandrosterone sulphate (DHEA-S), midnight F, 24-h urine collection for cortisol (UFC), low-dose dexamethasone suppression test (LDDST), fasting glucose, insulin, and oral glucose tolerance test (OGTT). Primarily, SH was defined as F-post-LDDST>70 nmol/l and one more abnormality; several diverse cut-offs were also examined.

RESULTS

No difference was noted in age, body mass index, or prevalence of diabetes and impaired glucose tolerance between patients with UI and those with BI. Patients with BI had higher F-post-LDDST (119·3 ± 112·8 vs 54·3 ± 71·5 nmol/l, P<0·001) and lower DHEA-S (1·6 ± 1·5 vs 2·5 ± 2·3 μmol/l, P=0·003) but similar UFC, ACTH and midnight F levels, compared to UI. SH was significantly more prevalent in BI (41·5%vs 12·2%, P<0·001). Fourteen patients were operated on; four underwent bilateral interventions. In 10 patients, unilateral adrenalectomy on the side of the largest lesion resulted in significant improvement in F-post-LDDST (P=0·008) and a decrease in midnight F (P=0·015) levels.

CONCLUSIONS

Subclinical hypercortisolism is significantly more prevalent in bilateral incidentaloma patients, posing great dilemmas for its optimum management.