Abstract
SUMMARY: Connshing syndrome, a distinct subtype of primary aldosteronism (PA), is characterized by the co-secretion of aldosterone and cortisol from an adrenal adenoma. This condition complicates diagnosis and treatment, as cortisol co-secretion can interfere with adrenal vein sampling (AVS), the gold standard for determining lateralization in PA. We present a case of a 57-year-old woman with resistant hypertension and an adenoma in the left adrenal gland, diagnosed with PA. During the investigation, cortisol co-secretion was identified. AVS results were confounded by this co-secretion, complicating the interpretation of lateralization. Despite this, a presumptive diagnosis of unilateral aldosteronism was made, leading to the decision for adrenalectomy. Postoperative analysis confirmed the resolution of PA and normalization of aldosterone and cortisol levels. This case emphasizes the diagnostic challenges posed by cortisol co-secretion, which can distort AVS results and complicate treatment decisions. Further research is necessary to improve diagnostic accuracy and develop tailored management strategies for patients with Connshing syndrome. LEARNING POINTS: As the number of adrenal incidentalomas identified through imaging increases, more cases of Connshing syndrome are likely to be uncovered during biochemical evaluation. The co-secretion of aldosterone and cortisol from adrenal adenomas can interfere with diagnostic tests such as AVS, leading to misinterpretation of lateralization and complicating treatment decisions. It is important to explore alternative markers to cortisol, such as plasma metanephrines, to improve AVS accuracy and guide management decisions in patients with Connshing syndrome.