Primary aldosteronism (PA) is a frequent form of endocrine hypertension caused by aldosterone overproduction, principally from one adrenal gland or relatively equivalently from both (unilateral or bilateral disease). Unilateral forms are usually caused by an aldosterone-producing adenoma (APA) in which somatic mutations alter the properties of ion channels and ion pumps to disturb intracellular ion homeostasis leading to increased CYP11B2 (aldosterone synthase) transcription. Adrenal CYP11B2 immunohistochemistry aids the final histopathological diagnosis of PA and is central to a refined approach for the identification of aldosterone-driver variants. Adrenal histopathology is linked to postsurgical outcomes and abnormal aldosterone production from the unresected contralateral adrenal gland. Some bilateral forms of PA may be caused by distinct histopathologic lesions called aldosterone-producing micronodules that in some cases, may evolve into APAs.
