Duplicated adrenal veins in primary aldosteronism misdiagnosed with ectopic aldosteronoma due to apparent bilateral aldosterone suppression

Primary aldosteronism (PA) is considered the number one aetiology for secondary hypertension. Apart from confirmatory tests and localisation of PA determined by computed tomography (CT), adrenal venous sampling (AVS) is used to define whether aldosterone hypersecretion occurs inside one or both adrenal glands. However, even correctly-performed AVS may lead to undiagnostic results such as apparent bilateral adrenal suppression (apparent bilateral aldosterone suppression), in which the adrenal aldosterone-to-cortisol ratios (AC ratios) are decreased bilaterally compared to the peripheral blood sample, with several causes contributing to it.Here, we describe the case of a 48-year-old man who was referred to our department for further investigation with a history of refractory hypertension, hypokalaemia, and aortic dissection. His hypertension and hypokalaemia were initially attributed to ectopic aldosteronoma due to his adrenal CT scan and AVS results. However, the correct diagnosis of an adenoma with duplicated right adrenal veins (duplicated adrenal veins) due to apparent bilateral aldosterone suppression was confirmed during surgery.AVS is the gold standard accepted for PA subtyping, but sometimes when apparent bilateral aldosterone suppression is present, it can give ambiguous results. Duplicated right adrenal veins, may impact results, thus, AVS may not accurately provide evidence of unilateral hypersecretion for all PA patients. Repeat AVS or adrenal surgery can provide worthwhile diagnostic conclusions.The recognition and diagnosis of primary aldosteronism (PA) have increased in recent years and clinicians usually require adrenal venous sampling (AVS) to identify the affected side, and it’s crucial for further treatments of PA patients (surgery or medicine).We presented an example of unilateral aldosteronoma with duplicated adrenal veins whose AVS results suggested apparent bilateral aldosterone suppression (the adrenal venous aldosterone/cortisol ratios are bilaterally lower than the peripheral ratios). He was misdiagnosed with ectopic aldosteronoma due to computed tomography (CT) features, but surgery findings revealed duplicated adrenal veins.Unclear AVS results such as apparent bilateral aldosterone suppression can lead to a missed diagnosis of unilateral PA, preventing patients from receiving potentially curative adrenal resection.Our case can serve as an example for clinicians that encounter the same condition to provide further investigational clues to ensure the correct aetiological diagnosis for patients with PA.