Differences Between Bilateral Adrenal Incidentalomas and Unilateral Lesions

Area of Science:

• Endocrinology
• Oncology
• Radiology

Background:

• Adrenal incidentalomas are common findings during abdominal imaging.
• While unilateral adrenal lesions have established workups, bilateral incidentalomas are less understood.
• Limited data exists on the natural history and clinical implications of bilateral adrenal incidentalomas.

Purpose of the Study:

• To compare the natural history of patients with bilateral adrenal incidentalomas versus those with unilateral adrenal incidentalomas.
• To identify differences in prevalence of endocrine disorders between bilateral and unilateral adrenal incidentalomas.
• To inform clinical management strategies for patients with bilateral adrenal incidentalomas.

Main Methods:

• Retrospective analysis of a prospective database from a tertiary care university hospital.
• Inclusion of 500 patients with adrenal lesions evaluated between July 2009 and July 2014.
• Comparison of patient demographics, imaging characteristics, biochemical workup, interventions, and diagnoses between bilateral and unilateral incidentaloma groups.

Main Results:

• Twenty-three patients had bilateral incidentalomas, and 112 had unilateral incidentalomas.
• Bilateral incidentalomas showed a higher prevalence of subclinical Cushing syndrome (21.7% vs 6.2%) and a lower prevalence of pheochromocytoma (4.3% vs 19.6%) compared to unilateral lesions.
• Rates of hyperaldosteronism were similar between groups; no occult adrenocortical carcinomas were found.

Conclusions:

• Bilateral adrenal incidentalomas are significantly associated with subclinical Cushing syndrome and less frequently with pheochromocytoma.
• Despite similar workups, the distinct natural history of bilateral incidentalomas necessitates a higher index of suspicion for subclinical Cushing syndrome.
• These findings underscore the importance of tailored diagnostic approaches for bilateral adrenal incidentalomas.