Morphometric and Histopathological Characteristics of Aldosterone-Producing Adenoma: A Tissue Microarray Study

Presentation Number: OR10-3
Date of Presentation: April 3rd, 2017

Yara Rhayem*1, Annette Feuchtinger2, Christine Woischke1, Philippe Ludwig1, Thomas Kunzke3, Thomas Schwarzmayr4, Stefanie Hahner5, Celso E. Gomez-Sanchez6, Tim M. Strom4, Thomas Kirchner1, Martin Reincke1, Axel Walch2 and Felix Beuschlein1
1Klinikum der Universität München, Ludwig-Maximilian University, Munich, Germany, 2Helmholtz Zentrum München, Neuherberg, Germany, 3Institute of Pathology, Helmholtz Zentrum München, Neuherberg, Germany, 4Helmholtz Zentrum München and Technische Universität München, Munich, Germany, 5University of Würzburg, Würzburg, Germany, 6University of Mississippi Medical Center, Jackson, MS

Abstract

Primary aldosteronism (PA), the most relevant cause of endocrine related hypertension, frequently presents as sporadic aldosterone-producing adenoma (APA). Laparoscopic unilateral adrenalectomy is the treatment of choice for this unilateral form of the disease. Next generation sequencing techniques have identified somatic mutations in APA harbored in KCNJ5, ATP1A1, ATP2B3, CACNA1D, CTNNB1 and PRKACA genes. The mechanisms involved in aldosterone overproduction are linked to overexpression of the CYP11B2 gene coding for aldosterone synthase, the rate-limiting enzyme for aldosterone biosynthesis. Yet, as much as half of the APA harbor no mutations in candidate genes (designated as wild type, WT) and little is known about genotype/phenotype correlation. Therefore, we investigated the tissue based molecular and histopathological characteristics of 132 APAs obtained after unilateral adrenalectomy in PA patients. Tumor DNA was screened for somatic mutations in candidate genes by targeted (n=84) or whole-exome (n=48) sequencing. We performed H&E and immunohistochemistry (IHC) for steroidogenic enzymes CYP11B1, CYP11B2, CYP17, HSD3B1 and HSD3B2 on tumor tissue microarrays from all samples. Visual scoring was replaced by digital image analysis to accurately quantify morphometric and IHC parameters. Morphometry analysis included 179 color, shape and texture features of different cell compartments such as cytoplasm and nucleus. The quantitative IHC was digitally analyzed and compared between tissues. Prevalence of WT APA in our cohort was 34%, more frequent in men (47.4%) than in women (16.1%) who presented most frequently with KCNJ5 mutated APA (62.5%). In 8/48 APA non-recurrent somatic mutations (NR) were identified. H&E analysis demonstrated that 6 morphometric parameters correlated negatively with WT status whereas those same parameters correlated positively with the presence of KCNJ5 or NR (P<0.01). The same reversed pattern between WT and KCNJ5 mutated APA was found in 10 cytoplasmic parameters, including mainly color-based features (P<0.01). KCNJ5 mutation status was negatively correlated with CYP11B1 and HSD3B1 expression (P<0.01). On the contrary, WT, CACNA1D and NR APA significantly correlated positively with CYP11B1. ATP1A1 mutated APA correlated positively with CYP11B2 (P<0.01) and not with CYP11B1 or HSD3B2. Independently, HSD3B1 expression correlated most frequently with CYP11B1 (P<0.01) and not CYP11B2 which correlated positively with HSD3B2 (P<0.01). Our findings in NR APA point towards a KCNJ5 like morphometric pattern associated with a WT like steroidogenic enzymes expression pattern. WT APA presented an opposed morphometric pattern in comparison to mutated APA, indicating that in absence of detectable somatic mutations APA cells are driven towards a different cellular fate.

 

Nothing to Disclose: YR, AF, CW, PL, TK, TS, SH, CEG, TMS, TK, MR, AW, FB