The mechanisms regulating cortisol production when ACTH of pituitary origin is suppressed in primary adrenal causes of Cushing's syndrome (CS) include diverse genetic and molecular mechanisms. These can lead either to constitutive activation of the cAMP system and steroidogenesis or to its regulation exerted by the aberrant adrenal expression of several hormone receptors, particularly G-protein coupled hormone receptors (GPCR) and their ligands. Screening for aberrant expression of GPCR in bilateral macronodular adrenal hyperplasia (BMAH) and unilateral adrenal tumors of patients with overt or subclinical CS demonstrates the frequent co-expression of several receptors. Aberrant hormone receptors can also exert their activity by regulating the paracrine secretion of ACTH or other ligands for those receptors in BMAH or unilateral tumors. The aberrant expression of hormone receptors is not limited to adrenal CS but can be implicated in other endocrine tumors including primary aldosteronism and Cushing's disease. Targeted therapies to block the aberrant receptors or their ligands could become useful in the future.
Nada El Ghorayeb, Isabelle Bourdeau, and André Lacroix
Isabelle Bourdeau, Nada El Ghorayeb, Nadia Gagnon, and André Lacroix
The investigation and management of unilateral adrenal incidentalomas have been extensively considered in the last decades. While bilateral adrenal incidentalomas represent about 15% of adrenal incidentalomas (AIs), they have been less frequently discussed. The differential diagnosis of bilateral incidentalomas includes metastasis, primary bilateral macronodular adrenal hyperplasia and bilateral cortical adenomas. Less frequent etiologies are bilateral pheochromocytomas, congenital adrenal hyperplasia (CAH), Cushing’s disease or ectopic ACTH secretion with secondary bilateral adrenal hyperplasia, primary malignancies, myelolipomas, infections or hemorrhage. The investigation of bilateral incidentalomas includes the same hormonal evaluation to exclude excess hormone secretion as recommended in unilateral AI, but diagnosis of CAH and adrenal insufficiency should also be excluded. This review is focused on the differential diagnosis, investigation and treatment of bilateral AIs.
Marie-Josée Desrochers, Matthieu St-Jean, Nada El Ghorayeb, Isabelle Bourdeau, Benny So, Éric Therasse, Gregory Kline, and André Lacroix
Unilateral aldosteronomas should suppress renin and contralateral aldosterone secretion. Complete aldosterone suppression in contralateral adrenal vein sample (AVS) could predict surgical outcomes.
To retrospectively evaluate the prevalence of basal contralateral suppression using Aldosterone (A)contralateral(CL)/Aperipheral(P) as compared to (A/Cortisol(C)CL)/(A/C)P ratio in primary aldosteronism (PA) patients studied in two Canadian centers. To determine the best cut-off to predict clinical and biochemical surgical cure. To compare the accuracy of ACL/AP to the basal and post-ACTH lateralization index (LI) in predicting surgical cure.
In total, 330 patients with PA and successful AVS were included; 124 lateralizing patients underwent surgery. Clinical and biochemical cure at 3 and 12 months were evaluated using the PASO criteria.
Using ACL/AP and (A/C)CL/(A/C)P at the cut-off of 1, the prevalence of contralateral suppression was 6 and 45%, respectively. Using ROC curves, the ACL/AP ratio is associated with clinical cure at 3 and 12 months and biochemical cure at 12 months. (A/C)CL/(A/C)P is associated with biochemical cure only. The cut-offs for ACL/AP offering the best sensitivity (Se) and specificity (Sp) for clinical and biochemical cures at 12 months are 2.15 (Se: 63% and Sp: 71%) and 6.15 (Se: 84% and Sp: 77%), respectively. Basal LI and post-ACTH LI are associated with clinical cure but only the post-ACTH LI is associated with biochemical cure.
In lateralized PA, basal contralateral suppression defined by ACL/AP is rare and incomplete compared to the (A/C)CL/(A/C)P ratio and is associated with clinical and biochemical postoperative outcome, but with modest accuracy.