Aldosterone-producing
adenoma (APA) cause primary
aldosteronism-the most frequent form of secondary
hypertension. Somatic mutations in genes coding for
ion channels and
ATPases are found in APA and in
aldosterone-producing cell clusters. We investigated the genetic, cellular, and molecular heterogeneity of different
aldosterone-producing structures in adrenals with APA, to get insight into the mechanisms driving their development and to investigate their clinical and biochemical correlates. Genetic analysis of APA,
aldosterone-producing cell clusters, and secondary nodules was performed in adrenal tissues from 49 patients by next-generation sequencing following
CYP11B2 immunohistochemistry. Results were correlated with clinical and biochemical characteristics of patients,
steroid profiles, and histological features of the
tumor and adjacent adrenal cortex. Somatic mutations were identified in 93.75% of APAs.
Adenoma carrying KCNJ5 mutations had more clear cells and cells expressing
CYP11B1, and fewer cells expressing
CYP11B2 or activated β-
catenin, compared with other mutational groups.
18-hydroxycortisol and
18-oxocortisol were higher in patients carrying KCNJ5 mutations and correlated with histological features of
adenoma; however, mutational status could not be predicted using
steroid profiling. Heterogeneous
CYP11B2 expression in KCNJ5-mutated
adenoma was not associated with genetic heterogeneity. Different mutations were identified in secondary nodules expressing
aldosterone synthase and in independent
aldosterone-producing cell clusters from adrenals with
adenoma; known KCNJ5 mutations were identified in 5
aldosterone-producing cell clusters. Genetic heterogeneity in different
aldosterone-producing structures in the same adrenal suggests complex mechanisms underlying APA development.