SUN-425 - Presentation and Clinical Patterns of Bilateral Adrenal Lesions: A Retrospective Cohort Study

Abstract

Context
Clinical characteristics of bilateral adrenal tumors, including concordant versus discordant etiologies and synchronous versus asynchronous presentation, are not well-defined.

Objective
To determine the etiological spectrum of bilateral adrenal masses and compare clinical patterns by concordance and synchronicity.

Methods
We performed a retrospective cohort study (2010-2025) of patients with bilateral adrenal tumors. A reference standard for etiology of each adrenal lesion was assigned using predefined clinical, imaging, and pathology-based criteria. Etiologies were compared by concordance and synchronicity. Multivariable logistic models were used to explore associations with having malignancy or pheochromocytoma as second adrenal mass.

Results
Among 815 patients (median age at first mass diagnosis 59.8 years [IQR 51.9-67.0]; 433, 53% women) with bilateral adrenal masses, 695 (85%) had concordant and 120 (15%) had discordant etiologies. Concordant cases were predominantly bilateral benign cortical lesions (534, 77%), whereas discordant cases showed a variable etiological distribution, with discordant benign lesions (41, 34%) and discordant malignant lesions (37, 31%) both comprising nearly one-third of cases.

Presentation was synchronous in 679 (83%) and asynchronous in 136 (17%) patients, with a median time interval between first and second adrenal mass of 3.8 years (IQR 1.3-6.1). Asynchronous tumors were less likely than synchronous tumors to be bilateral benign lesions (57% vs 74%) and more likely to be bilateral malignant non-adrenocortical carcinoma (17% vs 6%) or discordant malignant lesions (8% vs 4%); Chi-square test P < 0.001.

Among asynchronous cases, patients with shorter time between discovery of first and second adrenal mass were more often found to have a second adrenal mass that was a malignant non-adrenocortical carcinoma lesion compared to those with longer time intervals( < 2 years vs 2-4.9 years vs≥5 years: 40% vs 19% vs 9%), whereas patients with longer time intervals were more often found to have a second adrenal mass of a benign cortical lesion ( < 2 years vs 2-4.9 years vs ≥5 years: 45% vs 63% vs 61%) ; Fisher’s exact test P< 0.001.

In a multivariable logistic model that included age, larger second-lesion size (OR 1.07 per 1 mm, 95% CI 1.02-1.14) and < 2 years duration between first and second adrenal mass diagnosis (OR 4.07, 95% CI 1.26-13.14 compared to ≥5 years) were independently associated with a second adrenal mass of malignancy or pheochromocytoma.

Conclusion
Approximately one in six patients was diagnosed with either bilateral adrenal lesions of discordant etiology or asynchronous disease. In patients with asynchronous lesions, larger tumor size and a shorter interval to development of the second adrenal mass were associated with malignancy or pheochromocytoma.

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