A cross-sectional study of more than 25,000 adults has found that with increased screening, the prevalence of adrenal tumors in an unselected community population was 1.4%. The prevalence increased with age, from 0.2% in adults aged 18 to 25 up to 3.2% in adults older than 65 years of age. However, approximately 70% of identified tumors were nonfunctioning, meaning they did not make extra hormones, regardless of the participant's age. The findings are published in Annals of Internal Medicine.

The detection rate of adrenal incidentaloma, or an incidentally found nodule not causing clinical symptoms, has increased as screening techniques have improved and become more common. However, most published literature on the prevalence of adrenal incidentalomas consists of retrospective surveys based on radiographic diagnosis in a medical record system, which might under- or overestimate the prevalence.

Researchers from the First Affiliated Hospital of Chongqing Medical University, Chongqing, China, conducted a cross-sectional study of 25,356 participants receiving annual health assessments between November 2020 and November 2021. The authors report that of all 25,356 participants, 351 persons were identified as having adrenal tumors. Of these, 337 participants with adrenal tumors were diagnosed with an adrenocortical adenoma and 14 were diagnosed with another benign nodule. No participants were diagnosed with having a malignant mass. The authors also report that of 212 participants who completed endocrine testing, 69.3% were diagnosed with a nonfunctioning adenoma, 18.9% with cortisol autonomy, 11.8% with primary aldosteronism, and no participants were diagnosed with pheochromocytoma.

An accompanying editorial from Mayo Clinic highlights how this research provides important insights into the prevalence of adrenal tumors and supports current recommendations for universal hormonal testing in any patient with an incidentally found adrenal tumor. However, the author cautions that the study is limited by the lack of hormonal testing in 37% of participants, particularly because persons who declined hormonal work-up were older and more likely to have hypertension. As such, both mild autonomous cortisol secretion and primary aldosteronism could have been more prevalent in this group.