Are Small Adrenal Incidentalomas Solely a Radiological Finding?

Objective: The criterium defining the threshold size of adrenal incidentaloma (AI) is a size greater than 1cm diameter. However, data concerning AI≤1cm in diameter is scant. The aim of this study was to evaluate the function of adrenal masses≤1cm and to compare them with adrenal masses>1cm. Materials and Methods: The study included 130 consecutive patients with AI (38 and 92 AI at ≤1cm and >1cm, respectively). The patients were evaluated according to demographic and hormonal characteristics. Results: The prevalence of SCS was 5.3 and 12% in AI≤1cm and >1cm diameter, respectively. Hyperaldosteronism was found only in patients with >1cm AI. Pheochromocytoma were not found in either group. Patients with >1cm AI had a higher prevalence of SCS and primary hyperaldosteronism than patients with ≤1cm AI, but the difference was not significant. The prevalence of diabetes and hypertension was high both in non-functional AI with ≤1cm and >1cm patients and showed no significant difference between the 2 groups. Conclusion: Our study is the first to focus on the clinical and hormonal characteristics of patients with ≤1cm AI. Those with AI≤1cm harboured SCS, as was the case for AI>1cm. Similar to AI>1cm, non-functional AI≤1cm also had a higher prevalence of diabetes and hypertension.