SUN-195 Bilateral Aldosterone-Producing Adenomas: A New Subtype of Bilateral Primary Aldosteronism?

Background: Primary aldosteronism (PA) is the most common cause of endocrine hypertension (HT). PA subtypes include aldosterone-producing adenomas (APA) and bilateral adrenal hyperplasia. To date, few PA patients with bilateral adenomas have been reported, but only one case was well characterized by anatomopathological analysis and clinical outcome after adrenal sparing surgery (1). Clinical case: A 53-year-old woman was referred to investigate resistant HT and hypokalemia. (3.0 mEq/L). PA screening revealed aldosterone (A) of 37.9 ng/dL, renin (R) < 1.6 (4.4-46.1 mUI/L), A/R ratio of 24.8. Confirmatory testing confirmed PA diagnosis: seated saline infusion test (A= 83.3 ng/dL) and intravenous furosemide test (R= 3.1 mUI/L; positive test <13 mUI/L). Hypercortisolism investigation revealed a non-suppressible cortisol after an overnight 1 mg low-dose dexamethasone suppression [cortisol (C)= 2.9 μg/dL and dexamethasone= 701 (˃130 ng/dL)], and normal urinary free cortisol, midnight salivary cortisol, plasma DHEAS and ACTH levels. Computed tomography demonstrated bilateral adrenal nodules without adrenal thickening: 3.5 cm right nodule (pre-contrast density of 7UH density; absolute wash-out of 71%) and 2.5 cm left nodule (pre-contrast density of 8UH density; absolute wash-out of 78%). Sequential adrenal venous (AV) sampling (AVS) under continuous cosyntropin infusion showed a lateralization index of 3.4 (bilateral disease <4). Then, the patient underwent right adrenalectomy and left nodulectomy. In the postoperative period, she presented normalization of K(+) levels and complete HT remission. She remained under hydrocortisone replacement for 2 months. After 2 months, biochemical evaluation revealed normal basal cortisol levels (13.3 µg/dL) and biochemical cure of PA (A= 3.1 ng/dL and R= 15.3 mUI/L). Currently, she doesn’t have symptoms of adrenal insufficiency after discontinuation of hydrocortisone. Anatomopathological analysis showed bilateral adenomas (Weiss score of 0) in both sides without adjacent hyperplasia. CYP11B2 immunohistochemistry displayed a strong staining in 50% of cells in the right adenoma and in 30% of cells in the left adenoma. Few aldosterone-producing cell clusters (APCC) were identified in the right zona glomerulosa, which is a frequent finding in normal adrenals. Conclusion: We herein described a very rare case of PA caused by bilateral-producing adenomas, confirmed by AVS and CYP11B2 staining after adrenal sparing surgery.