Clinical and Metabolic Characteristics and Follow-Up Results of Adrenal Incidentalomas: A 10-Year Experience

In this retrospective study, we aimed to investigate the clinical, hormonal, and radiological characteristics of patients with adrenal incidentalomas (AIs), to assess the prevalence of metabolic syndrome components in patients with AIs, and to determine whether changes in tumor size or hormonal activity occur during long-term follow-up in patients with AIs.

We retrospectively analyzed data from 384 patients diagnosed with AI between 2010 and 2020. Data regarding radiological, hormonal, and metabolic investigations in diagnosis and also during follow-ups were collected.

A total of 384 patients (248 female, 64%) enrolled in this study. Of them, 348 (90.6%) of the masses were classified as adenomas, 31 (8.07%) as non-adenomas, and four (1.04%) were non-specified. The mean adenoma diameter was approximately 2 cm. Adenomas were found to be mostly on the left side (48.9%). Overall, 13.81% (n = 53) of the tumors were functioning, and among functional adenomas, nine patients (2.34%) had autonomous cortisol secretion, seven subjects (1.82%) had primary hyperaldosteronism, four subjects (1.04%) had pheochromocytomas, and 39 subjects (10.1%) had possible autonomous cortisol secretion. In patients with bilateral incidentalomas, the mean diameter of adenomas was higher than unilateral incidentalomas with a diameter of 24.22 mm in comparison to 20.36 mm (p > 0.05). Similarly, in patients with bilateral incidentalomas, systolic and diastolic blood pressure was higher than in unilateral incidentalomas (135.83 ± 20.27, 130.02 ± 18.84 and 79.25 ± 11.56, 78.52 ± 10.11, respectively, p > 0.05). Moreover, our study revealed that the frequency of diabetes, hypertension, and hyperlipidemia in patients with possible autonomous cortisol secretion was 37%, 63%, and 22.2%, respectively. Of 384 patients, 9.11% (n = 35) underwent surgery. The most common pathological finding was adrenocortical adenoma (n = 19, 54%). The median follow-up duration of patients was 48.91 months. Of 384 patients, 44.7% (n = 172) were followed up regularly with CT/MRI. During the follow-ups, the diameter of adenomas (11.6%) increased by more than 10 mm. Of 384 subjects, 56.7% (n = 218) of patients were followed with hormonal evaluation, six patients had developed possible autonomous cortisol secretion, and three patients had developed autonomous cortisol secretion. Moreover, one subject developed primary hyperaldosteronism.

In this retrospective study, we examined the clinical, radiological, and hormonal profiles of patients with AIs, finding results consistent with existing literature. The conversion to subclinical or clinical hypercortisolism was low, and no new cases of pheochromocytoma were observed, with only one case of primary hyperaldosteronism. Most of the adenomas showed minor growth in size over time, and a small percentage developed hormonal hyperfunctionality. Our study also identified an increased risk of diabetes, hypertension, hyperlipidemia, and metabolic syndrome in AI patients. Additionally, patients with unilateral adenomas had higher triglyceride levels and insulin resistance than those with bilateral adenomas.