Primary Hyperaldosteronism Caused by Bilateral Adrenal Hyperplasia and a Unilateral Adrenal Adenoma: A Diagnostic and Therapeutic Challenge (Case Report)

Background Primary aldosteronism (PA) is the most common endocrine cause of secondary hypertension. Accurate diagnosis is essential, especially in patients with refractory hypertension and hypokalemia. Differentiating between aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH) is critical to guide management, however the coexistence of both is extremely rare but clinically significant. Case presentation: We report the case of a 49-year-old woman with poorly controlled hypertension and recurrent episodes of hypokalemia and hypocalcemia, leading to multiple hospital admissions. Computed tomography (CT) revealed a right adrenal hypodense lesion consistent with an adenoma. However, adrenal venous sampling (AVS) indicated dominant aldosterone secretion from the left adrenal gland, and biopsy confirmed left-sided hyperplasia. This discordance between imaging and hormonal function posed a diagnostic and therapeutic challenge. Intervention and outcomes: Based on biochemical lateralization and after multidisciplinary evaluation, a left unilateral adrenalectomy was performed. The patient had no surgical complications. At six-month follow-up, blood pressure was controlled with only two antihypertensive agents and no additional complications. Hormonal re-evaluation showed biochemical improvement. Conclusion This case illustrates the limitations of relying solely on imaging in PA. The coexistence of a non-functioning adrenal adenoma and contralateral functional hyperplasia is rare but clinically significant. AVS remains the gold standard for lateralization and should guide surgical decisions. An individualized approach, prioritizing biochemical over radiological findings, can improve outcomes even in complex or bilateral secretion scenarios.