Primary adrenal hyperplasia: a new subset of primary hyperaldosteronism.

The existence of a new subset of primary hyperaldosteronism that combines the morphology of bilateral hyperplasia with the biochemical and therapeutic responses typical of adenoma recently was suggested. The following is the first detailed case report of that subset. The patient had severe hypokalemia and hypertension responsive to spironolactone, and elevated supine plasma aldosterone and 18-hydroxycorticosterone values that did not increase after ambulation. Surgical removal of 75% of both adrenal glands decreased mineralocorticoid levels into the low normal range and allowed the return of normal renin-angiotensin function, although plasma aldosterone was still unresponsive to postural change. Glucocorticoid reserve remained normal. Histology showed bilateral cortical hyperplasia. The results support the existence of a new subset of adrenal hyperplasia, termed primary adrenal hyperplasia, in which biochemical parameters and response to surgery mimic those of adrenal adenomas. The existence of such a subset indicates that morphological categorization alone is insufficient to rule out a possible therapeutic response to surgery in patients with aldosterone-secreting adrenal hyperplasia.