Clinical and Imaging Presentations are Associated with Function in Incidental Adrenocortical Adenomas – a Retrospective Cohort Study

Abstract Objective The aim of this study is to assess whether clinical and imaging characteristics are associated with the hormonal subtype, growth, and adrenalectomy for incidental adrenal cortical adenomas (ACAs). Design This is a single-center cohort study. Methods Consecutive adult patients with incidental ACA were diagnosed between 2000 and 2016. Results Of the 1516 patients with incidental ACA (median age 59 years, 62% women), 699 (46%) had nonfunctioning adenomas (NFAs), 482 (31%) had mild autonomous cortisol secretion (MACS), 62 (4%) had primary aldosteronism (PA), 39 (3%) had Cushing syndrome, 18 (1%) had PA and MACS, and 226 (15%) had incomplete work-up. Age, sex, tumor size, and tumor laterality, but not unenhanced computed tomography Hounsfield units (HU), were associated with hormonal subtypes. In a multivariable analysis, ≥1 cm growth was associated with younger age (odds ratio [OR] = 0.8 per 5-year increase, P = .0047) and longer imaging follow-up (OR = 1.2 per year, P < .0001). Adrenalectomy was performed in 355 (23%) patients, including 38% of MACS and 15% of NFA. Adrenalectomy for NFA and MACS was more common in younger patients (OR = 0.79 per 5-year increase, P = .002), larger initial tumor size (OR = 2.3 per 1 cm increase, P < .0001), ≥1 cm growth (OR = 15.3, P < .0001), and higher postdexamethasone cortisol (OR = 6.6 for >5 vs <1.8 μg/dL, P = .002). Conclusions Age, sex, tumor size, and laterality were associated with ACA hormonal subtype and can guide diagnosis and management. Tumor growth was more common with younger age and longer follow-up. Unenhanced HU did not predict hormonal subtype or growth. Adrenalectomy for MACS and NFA was mainly performed in younger patients with larger tumor size, growth, and elevated postdexamethasone cortisol.