Some Conn'S Adenoma Can Be Missed By The Cortisol-Normalized Adrenal Venous Sampling

Objective: To analyze discordances between lateralization predicted by CT scan or by adrenal venous sampling (AVS) in patients with primary aldosteronism (PA) and a unilateral adrenal mass. Design and method: Monocentric retrospective analysis of data of 33 selective AVS in patients with primary aldosteronism (PA) and a unilateral adrenal mass. In our center AVS is performed simultaneously on both adrenal veins (AV) without stimulation and analyzed not only with cortisol but also epinephrine as a reference for selectivity and lateralization. lateralization index (LI) > 4 is considered significant. Immunohistochemical analysis of CYP11B1, CYP11B2 and CYP17 was performed in the adrenal adenoma of one patient. Results: One patient with severe hypertension and hypokalemia showed PA, no hypercortisolism and a 2 cm right adrenal mass. AVS was selective in both AV and cortisol-normalized AVS showed right/left LI = 0.8, ruling out lateralization, despite the fact that absolute values of aldosterone, but also cortisol, were higher in the right AV. By contrast epinephrine-normalized AVS showed right/left LI = 6.25 as absolute values of epinephrine were similar in both AV. The patient was treated medically but showed poor tolerance of anti-aldosterone treatment and eventually underwent right adrenalectomy, resulting in normalization of blood pressure and remission of PA. Immunochemical analysis of his right adrenal adenoma showed expression of CYP11B2 but also CYP11B1 and CYP17. Analysis of the 32 other patients identified 5 discordances between cortisol-normalized AVS lateralization and epinephrine-normalized AVS, with 2/5 patients showing concordance in epinephrine-normalized AVS and CT scan. These 2 patients were not operated as cortisol-normalized AVS was still considered the standard. Conclusions: Cortisol-normalized AVS can fail to detect lateralization of aldosterone secretion by Conn's adenoma expressing not only CYP11B2 but also CYP11B1 and CYP17, which must allow secretion of not only aldosterone but also cortisol, without being necessary responsible for hypercortisolism. In these adenoma cortisol measurements during AVS is not a reliable reference to normalize aldosterone, as it is produced by both the normal adrenal gland and the adenoma.