Clinical, radiological, and surgical outcomes of 431 patients with adrenal incidentalomas: retrospective study of a 10-year single-center experience

Abstract

Background/aim: The incidence of adrenal tumors is increasing due to the widespread utilization of radiographic imaging techniques. Factors such as tumor size, radiological characteristics, and functionality of adrenal adenomas play crucial roles in diagnosis and subsequent management. In this retrospective study, we investigated the clinical, radiological, and surgical features of patients with adrenal incidentalomas (AIs) and evaluated their follow-up results. Materials and methods: We analyzed data from 431 patients diagnosed with AIs (130 males, 301 females) who underwent adrenal hormone evaluation at our center. We compared nonfunctioning and functioning AIs in terms of radiological features. We also compared baseline and follow-up characteristics in nonfunctioning AIs. Results: The mean age of the patients was 55.4 +/- 11.5 years, with a mean tumor size of 25.9 +/- 14.3 mm. Mean follow-up duration was 3.17 +/- 2.07 years. Adenoma localization revealed 165 (38.3%) right-sided, 185 (42.9%) left-sided, and 81 (18.8%) bilateral cases. Most patients (76.6%) had nonfunctioning AIs. During follow-up, nonfunctioning AIs exhibited increased fasting blood glucose, fasting insulin and HOMA-IR values (p = 0.002, <0.001 and 0.004, respectively). Among the functioning AIs cases (23.4%), autonomous cortisol secretion, Cushing's syndrome, pheochromocytoma, and primary aldosteronism were observed in 10.4%, 5.1%, 3.9%, and 3.9% of cases, respectively. Receiver operating characteristic curve analysis determined an adrenal adenoma size of 26.5 mm as the optimal cut-off for distinguishing between functioning and nonfunctioning AIs, with a sensitivity and specificity of 61.4% and 70.0%, respectively. Conclusion: Although the majority of AIs are nonfunctioning, the prevalence of functioning adrenal adenomas is not rare. Our findings suggest that adenoma size emerges as a valuable predictor for early detection of functioning adenomas. In addition, smaller masses appear to carry a lower risk of malignancy.