Immunohistochemical and Genetic Analysis of Aldosterone Producing Adenomas Demonstrating Discrepancy Between Pre- and Post-ACTH Diagnoses in Adrenal Venous Sampling

Presentation Number: LB SUN 49
Date of Presentation: April 2nd, 2017

Daisuke Aono*1, Mitsuhiro Kometani2, Shigehiro Karashima2, Takashi Yoneda3, Koshiro Nishimoto4 and Yoshiyu Takeda3
1Kanazawa university, Kanazawa Ishikawa, JAPAN, 2Kanazawa University, Kanazawa, Japan, 3Kanazawa University, Ishikawa, Japan, 4Tachikawa Hospital, Tokyo, Japan

Abstract

Context: The use of adrenocorticotropic hormone (ACTH) is recommended in adrenal venous sampling (AVS) for primary aldosteronism (PA) to improve the success rate. However, it sometimes causes confusion of subtype diagnosis. Pathological characteristics such as somatic mutation may be related to lateralization on AVS.

Objective: The aim of our study was to investigate the influence of immunohistochemical and genetic characterization of aldosterone-producing adenoma (APA) on AVS.

Methods: We evaluated 17 PA patients, who were performed unilateral adrenalectomy from 2011 to 2015 in our center. All surgical specimens were immunostained for CYP11B2 and CYP11B1. We used lateralization criteria of lateralization index of > 2 pre-ACTH and > 4 post-ACTH, and made a comparison between pre- and post-ACTH diagnoses. We analyzed somatic mutations identified in APA.

Results: Among 17 surgical cases, 11 patients had an APA showed positive immunostaining for CYP11B2. Of them, five were unilateral both before and after ACTH stimulation (ACTH-S), and six were unilateral before ACTH-S and bilateral after ACTH-S. In immunohistochemical analysis, the frequency of the cases with multiple aldosterone-producing cell clusters (APCC) in adjacent adrenal gland was significantly higher in the unilateral cases in only pre-ACTH diagnosis than unilateral cases in both pre- and post-ACTH diagnoses (83% vs 0%, P=0.02). In genetic analysis, the frequency of the cases with KCNJ5 mutations was lower in the unilateral cases in only pre-ACTH diagnosis than unilateral cases in both pre- and post-ACTH diagnoses, but not significantly (67% vs 80%). There were no cases with other gene mutations.

Conclusions: Our immunohistochemical analysis suggested that the condition in adjacent adrenal gland of APA was one of the factors that affected the lateralization of AVS in PA.

 

Nothing to Disclose: DA, MK, SK, TY, KN, YT