SUN-431 - Combination Medical Therapy for Concurrent Primary Aldosteronism and Mild Autonomous Cortisol Secretion Prior to Targeted Adrenal Ablation

Background: Concurrent primary aldosteronism (PA) and mild autonomous cortisol secretion (MACS) occurs in approximately 5-27% of patients with PA, presenting diagnostic and therapeutic challenges, particularly with bilateral adrenal adenomas. We presented a case with successful medical management of dual hormone excess from bilateral adrenal adenomas using combination mifepristone and spironolactone therapy, followed by planned radiofrequency ablation (RFA)

Case Presentation:
A 49-year-old woman with hypertension, episodic hypokalemia, uncontrolled type 2 diabetes mellitus requiring insulin, and morbid obesity had bilateral adrenal adenomas (left 2.2 cm, right 1.5 cm; both < 10 Hounsfield units). Biochemical evaluation revealed suppressed DHEA-S (17 µg/dL) and ACTH (10.1 pg/mL), dexamethasone suppression test cortisol of 1.8 µg/dL, elevated late-night salivary cortisol (0.177 µg/dL), and normal 24-hour urinary free cortisol, consistent with MACS. Aldosterone was elevated at 15.8 ng/dL with suppressed renin (0.4 ng/mL/h; aldosterone-to-renin ratio >30), suggesting PA, although captopril challenge showed post-test aldosterone < 10 ng/dL. Plasma and urine metanephrines were normal.
Adrenal vein sampling demonstrated lateralization of cortisol secretion to the left adrenal gland (left adrenal/IVC cortisol ratio 23, left-to-right gradient 2.7) with evidence of right adrenal cortisol production (right ratio 8.2), consistent with bilateral MACS.
The patient was treated with mifepristone 300 mg daily and spironolactone 25 mg daily, titrated to 600 mg and 100 mg, respectively. After 5 months, blood pressure improved with discontinuation of one antihypertensive agent, total daily insulin dose decreased by 50%, hemoglobin A1c improved from 9.7% to 7.2%, and body weight decreased by 10 lbs. The patient was planned for left adrenal radiofrequency ablation or left adrenalectomy.

Conclusion:
This case illustrates the complexity of managing concurrent PA and MACS in the setting of bilateral adrenal adenomas. Combination mifepristone and spironolactone therapy effectively controlled manifestations of both cortisol and aldosterone excess. Targeted interventional therapy, such as radiofrequency ablation of the dominant lesion, may represent a minimally invasive alternative to adrenalectomy in selected patients.

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