Partial Adrenalectomy Carries a Considerable Risk of Incomplete Cure in Primary Aldosteronism.

PURPOSE Laparoscopic adrenalectomy is standard treatment for patients with unilateral aldosterone-producing adenomas (APA), but surgeons are increasingly tempted to perform partial adrenalectomy (pAdx), disregarding potential multinodularity of the adrenal. We assess the diagnostic value of endoscopic ultrasound (EUS) for differentiating solitary adenomas from multinodularity by examining in depth adrenal pathology with ex vivo 11.7T MRI and immunohistochemistry (IHC). MATERIALS AND METHODS In fifteen primary aldosteronism (PA) patients, we performed intraoperative EUS, ex vivo MRI and histopathological examination. Every adrenal was intra-, and postoperatively assessed for solitary adenomas or multinodular hyperplasia (MNH). After unblinding for ex vivo MRI results a second detailed histopathological examination including IHC analysis with CYP11B2 (aldosterone synthase) and chemokine receptor 4 (CXCR4), a new marker for APA, was performed. Finally, presence of somatic mutations linked to APA were assessed. RESULTS The sensitivity and specificity of EUS to identify multinodularity was 46%, and 50%, respectively. We found MNH in 87% of adrenals with ex vivo MRI combined with detailed histopathology and six adrenals contained multiple CYP11B2 producing nodules. Every CYP11B2 positive nodule and 61% of CYP11B2 negative nodules showed CXCR4 staining. Finally, in four adrenals we found somatic mutations (27%). In multinodular glands, only one nodule harbored this mutation. CONCLUSIONS Intraoperative EUS in PA patients has low accuracy to identify multinodularity. Ex vivo MRI can serve as a tool to direct detailed histopathological examination, which frequently shows CYP11B2 production in multiple nodules. Therefore, pAdx is inappropriate in PA as multiple aldosterone producing nodules easily stay behind.