Primary aldosteronism is comprised of primary adrenal hyperplasia and adenoma.

Primary aldosteronism due to primary adrenal hyperplasia (PAH) is described. Hypertension, hypokalaemia, hyperaldosteronism and renin suppression were corrected by unilateral adrenalectomy in 3/5 patients and by spironolactone treatment in 2/5. Blood pressure and hormonal parameters have remained normal for up to seven years after surgery and spironolactone management. Four patients had bilateral micro- and macronodular hyperplasia and one had unilateral hyperplasia. While hormonally and biochemically identical to patients with aldosterone producing adenoma, PAH can be distinguished from idiopathic hyperaldosteronism (adrenal hyperplasia). The inability to demonstrate a tumour by computed tomography but the presence of bilateral elevations of aldosterone concentration in adrenal venous blood identifies PAH.