Comprehensive biochemical and radiological assessment of clinical characterization pertaining to bilateral adrenal masses: a multi-center cross-sectional investigation

BACKGROUND: Bilateral adrenal masses are increasingly diagnosed in routine clinical practice due to widespread use of radiological assessments. Although bilateral adrenal masses consist of heterogenous etiologies including hyperplasia and infiltrative lesions, a majority of them are adrenocortical adrenal lesions which are pathologically confirmed as adenomas. We aim to elucidate the clinical, biochemical, and radiological attributes in individuals exhibiting bilateral adrenal masses, utilizing an extensive sample cohort derived from various medical centers across our nation. METHODS: Retrospective analyses of 1250 patients (female vs. male, 774 vs. 476) with adrenal masses presenting from seventeen endocrine centers between 2010 and 2025 in Turkiye were carried out. Patients presenting with adrenal masses underwent comprehensive clinical, hormonal, and radiological evaluations. Data were obtained from centers located in different provinces across Turkey as part of the study, and a total of 1180 patients were included in the study. After the initial work-up hormonal assessment, the radiological evaluation of adrenal gland neoplasms was conducted employing both non-contrast and contrast-enhanced computed tomography (CT), as well as magnetic resonance imaging (MRI). All imaging acquisitions adhered to established protocols, and the analyses were executed by radiologists with expertise in abdominal imaging. In non-contrast computed tomography (CT) imaging, attenuation values of lesions were quantified in Hounsfield Units (HU), with lesions exhibiting values of ≤ 10 HU classified as indicative of lipid-rich adenoma. RESULTS: Mean age of all patients was 59.6 ± 10.7 and 735 patients (62.3%) had nonfunctioning adenoma (NF), 235 (19.9%) had autonomous cortisol secretion (ACS), 78 (6.6%) Cushing's syndrome (CS), and 132 (11.2%) were diagnosed with primary aldosteronism (PA) in the clinical diagnosis distribution. When clinical diagnosis groups (NF, ACS, CS, PA) were compared in terms of biochemical parameters, basal cortisol levels differed between the groups (p = 0.033). Furthermore, these levels were higher in the CS group than in the PA and NF groups (p = 0.015 and p = 0.022, respectively). ACTH, circadian cortisol at 23:00, and cortisol levels after 1 mg and 2 mg dexamethasone differed between the groups (p < 0.001). ACTH levels were found to be lower in ACS and CS compared to NF and PA (p < 0.001). The most common radiological diagnosis was adenoma (n = 1180, 92.3%). Radiological evaluation was available in 829 cases (74.0%), and the HU value in the right adrenal lesions was below 10 in 84.6% of the cases and was homogeneous in 92.2%. In the left adrenal lesions, the HU value was below 10 in 88% of the cases and 92.6% were assessed as homogeneous. MRI was available in 492 cases (41.3%), and 89% of the lesions evaluated in the dual echo sequence were consistent with fat-rich adenoma. A significant correlation between the clinical diagnosis and HU of adrenal masses (right and left sided) was not observed (p = 0.244, 0.215). Mean adenoma size of the right (20.7 ± 13.3 vs. 19.9 ± 12.5) and the left adenoma was similar. CONCLUSION: In the present study, a significant majority of the subjects were recognized as possessing non-functional adenomas, whereas the other participants were categorized as demonstrating ACS, CS, and PA during the clinical evaluation, respectively. A significant proportion of the patients displayed similar radiological properties concerning HU, defined by consistency despite the presence of hormonal attributes.